It's been a while since I was last here. Unfortunately I'm very busy these days so I ended up not playing much more of the mod. I was surprised to see so many updates!
Anyway, since it seems like I might not finish the game any time soon, I decided to do the write up I mentioned way back on my experience with the characters. Keep in mind I'm only at the Lunar Base so there are abilities and limits I haven't unlocked yet. Also keep in mind, this is all pre-1.3, so some of these may not be relevant.
Squall: Squall's good the way he is. He is very tanky and can deal very good physical damage, especially with Darkside. He might seems a bit weak early on, but once he gets towards LV 20, and gets abilities like Darkside, he really starts to pick up the slack. Only thing I might suggest as a change would be to give him Cura and maybe Life as additional spells. Cura would definitely give his white magic a bit more longevity and Paladins tend to have it in FF.
Squall started out a little rough, but I agree that he's in a good place now. I like the soft mechanic of fluctuating HP between Darkside, Defend, and Auto-Potion, as well as being able to utilize Defend's fractional HP penalty/Crisis Level bonus to make his Limits more effective.
This ties into your suggestion for Irvine, but I've been thinking about doing away with the magic restriction stuff altogether and leaving only Squall, Rinoa, and Selphie with the Magic command. Squall's Magic command would still be situationally useful for things like buffs and revives past the early game; I'd leave Rinoa's stats the same or close to it; and I'd lower Selphie's Magic stat so that she wouldn't be far better than Rinoa as soon as she gets Double.
Zell: Probably one of, if not the best party member. His high HP offsets his relatively weak defenses, his damage is really high and doesn't cost HP or spells. If I had trouble with a boss, swapping in Zell usually helped turned things around. He's really good, almost a bit too good when compared to the rest of the characters in terms of damage and survivability.
I agree that Zell is a little too good for how simple he is, so I nerfed his damage output in a previous update. He's still pretty good, though.
Selphie: Like Zell, she is really good. She is squishy but her damage output makes up for it. Selphie's straightforward like Zell, so there isn't much to say about her. She's easy to use, her spell selection is great, I really don't have any complaints. This is true even before unlocking her Double ability, and after she gets even better.
I think Selphie's only other drawback is that Slot isn't that useful past a certain point. I plan to adjust it again, though I also don't consider it a big problem since she's strong even without it. I've thought about nerfing her some, but haven't decided anything.
Rinoa: Rinoa functions perfectly well as a white mage and offensively Dia and Water get her by for the most part. Angelo's limits are strong too so that also helps. Nothing much to say about her stat-wise or anything, she is the necessary white mage and fulfills that role just fine.
On the subject of offense, I doubt most would do this but Rinoa with Shooting Star also makes a solid candidate for the copy of Darkside you get from Bahamut since the weapon makes her crit around a quarter of the time.
Quistis: Until she gets Aura, Quistis is pretty limited. It doesn't help that her physical damage isn't very good and Draw-casting is unreliable. Once she gets Aura and a few limits, she gets better but honestly, she still isn't very good. Even though her stats are balanced, she just doesn't do enough damage or have much in the way of utility. Apart from stealing, she's really only good for dealing damage with limits. While her limit selection is technically versatile, acquiring her limits takes more effort than those of any other character, and even then her damage with them isn't up to snuff. Sure she has various elemental attacks, but not only do you have to find them first, but once you do, characters like Selphie and Rinoa still outdamage her with their magic very noticeably. I had Selphie deal twice as much damage as Quistis constantly, if not more.
Plus given that you have to seek her limits out, the few defensive spells Quistis has that could give her some versatility aren't obtainable until much later. I'm at the Lunar Base and she still doesn't have Mighty Guard or White Wind for example, both of which would have been very useful in any boss battle up until now. I think she should get these particular limits much earlier to give her some much needed defensive capabilities that would make her uniquely useful. Additionally, the damage of her limits could use a boost.
Honestly, if not for her ability to steal, Quistis would have been a permanent bench-warmer for me because she was always a liability for bosses. She couldn't deal much damage, she couldn't take damage for long, she just isn't very good. I was struggling against Seifer in Galbadia Garden with Rinoa and Quistis in my party, once I switched her out for Zell, I won the fight on my first try.
I think you're selling Quistis short. Electrocute in particular is very easy to get before the end of Disc 1 and is pretty strong on Disc 2 due to all the sections in which you're fighting Galbadian mechs. While I nerfed its status affliction power somewhat in the last update, Bad Breath can be gotten as early as Disc 2 and is great in most random battles. Acid is another easy to get spell and is a consistent 900/1200 damage on any target, which is solid for Disc 2. Gatling Gun's Vit-ignoring properties come in handy as well. On Disc 3, she of course gets Mighty Guard, which is still plenty useful even after I nerfed its Crisis Level 1 properties; White Wind, which is easily the best healing ability (it's possible to get White Wind on Disc 2, but only as the rarest drop from mid-level Adamantoises, so I won't count it); and Homing Laser/Shockwave Pulsar, which are competitive with one another depending on the number of enemies and their Spr stat. Since discussing the character balance with Nikkolas a few months ago I've started to think that Zell or Selphie are the best characters overall, but I still think Quistis is the most solid by the end of the game, with no real weaknesses outside of a low Spd stat, and can be a lifesaver in certain fights.
With that said, I think you have a point about her early game being weak, and it doesn't help that she's out of the party for a significant portion of Disc 1. I think I'll bring her early Str/Vit up some. One question though: when did you make her second weapon? It's pretty easy to make as early as post-Dollet if you can get the Anacondaurs to drop Venom Fangs, and if not then, then after leaving Timber.
One change I considered and forgot about amidst everything else on my plate was making her breath attacks physical-based so that they'd scale better over the course of the game; I'd probably make it easier to get all of them on Disc 1 in such a case as currently, they're pretty strong for when you can first get them. I may start her with some AP in Aura/make it available earlier so that she learns it sooner. I've also been thinking about starting her off with Devour, not really to buff her but just to get it out of the way and
maybe encourage the player to try it.
The only spell I'd consider making available significantly earlier is Ray-Bomb. However, I've long thought about changing Degenerator into something else, perhaps a weak heal + Regen AoE that can be gotten sooner than White Wind. I'm open to suggestions from anyone, but keep in mind it would have to reuse one of Quistis' existing Blue Magic animations (and it can't be Degenerator's) and, preferably, isn't a worse version of something else she has.
Also, maybe I should reconsider which spells are "freebies" and which you need to go out of your way for. Because I didn't make drastic changes to what enemies appear where, the mod doesn't stray far from vanilla in this regard.
Irvine: Irvine's too gimmicky for his own good. His damage early on is really low and he isn't particularly good for anything until he gets Aura like Quistis. Later on he starts catching up, his damage gets better and his speed and critical rate start showing more potential. However I found him to be dead weight up until that point, mostly had him using healing items. I understand the idea behind the different guns but I'm honestly not a fan of that mechanic all, I'd prefer if he just had normal weapons like everyone. Overall, Irvine has the same problem that gimmicky characters like Gau from FF6 do: he can be useful if you put in the effort but when most other characters are easy to use, it makes him look worse.
I have a big suggestion for Irvine: turn him into a Red Mage. Give him Magic (and Draw?) and a spell list containing most of the basic and second level spells, plus some support ones. I was thinking Scan, Cure, Cura, Esuna, Haste, Slow, Fire, Fira, Thunder, Thundara, Blizzard, Blizzara, Water, Aero as must have spells for him, plus anything else you think is appropriate, like status-effect spells. Maybe Life?
Irvine has a pretty good magic stat and I decided to use him as a Red Mage, and it made him so much more useful. He isn't as good as the pure mages, but he's good enough at both offense and healing that he can be useful up until high-level spells start rolling in. Having both black and white magic as well makes him uniquely versatile early on, and is a great choice for elemental magic if you can't use Selphie or as a second healer if you don't want to use Rinoa. This is really good in particular during the prison and missile base sections where the party gets split up, having a second healer is super useful.
This would also help his late-bloomer stats. Early on he's not that fast or strong physically, but he has good magic, so he'd mostly be sticking to using spells to offset this. Toward the later parts of the game, as his magic starts lagging behind, his physical damage starts catching up and he gets more types of ammo, you'd start using his physical attacks and limit more. His spells would no longer be as useful later, since Thundaras can't keep up with Thundagas or high-end spells, but by then, he'd grow into the physical attacker he is. Sinceh he'd have Cura, he'd still be a decent secondary healer as well in a pinch.
Basically he'd be the classic Red Mage, a class that is really useful early on but not so good later, and by the endgame, he'd grow into a fast, high-critical rate Gunner, while still retaining his spells for emergencies if wanted. I think this would be better than he is now, plus Irvine always struck me as a hybrid character, who'd have a class that combines attacks and magic, not really sure why. Also, his GF should learn Call Shop to make buying ammo easier. I think Cerberus only has Junk Shop, which is less useful in my opinion.
I may make Irvine start out with Aura or GF to give him something else to do and to make Bismarck/Exeter more viable picks from the outset as well as adjust his Str stat to give his attacks a higher baseline. I also need to decide what to do with Fast Ammo...
While I like the Magic suggestion, I want there to be fewer "rules" on how to play the mod; that's one reason I removed Irvine's Magic command in 1.3. I touched on this above, but while I think the game is more fun when characters are assigned only certain spells, sometimes I think I should stop trying to shove a square peg into a round hole, if you will. It'd be great if I could actually make different Magic commands that allow for the casting of only certain spells, but that's beyond my ability. I dunno, maybe the final update will have two different versions depending on how you'd rather play the game.
On the subject of Irvine as healer, Exeter's power is only two points shy of Cura and works well enough if Rinoa isn't around (it can be Darksided for double the heal on Disc 3/4, which is fun but not exactly optimal). He can also learn Med Data starting from level 35, which makes him pretty good at healing as long as you have the items for it.
I gave Irvine Junk Shop so that he could more easily switch weapons. This is all subject to change, but one sidequest I'm planning will have Ammo-RF as a potential reward as early as the Missile Base as a way of getting ammo if you need it and can't get to a shop.
Well, that's all. I hope it will be useful. I'll still be keeping an eye on the mod in the future, although I'm not sure when I'll actually have the time to continue playing properly. :C
I appreciate the feedback

I'd love to hear your thoughts on the rest of the game whenever you get the time.