OK I will try them again with the update in any case I beat everything in Ultimecia's castle only Ultimecia herself is left so I'm gonna go in the order I did them :
-Sphinxaur : Well since we only have Normal Attacks this as a result is a very straight forward boss, I took all 3 boys junction Holy to their attack and I just keep attacking, he doesn't do that much damage, just have to be carefull hitting him and not the jelleye he summons in the second phase, I recover Magic and the 2 next bosses will be girls time.
-Tri Point : So the gimmick of this one is to alternate between Fire and Ice magic, so I use Triple on all 3 girls and Rinoa and Quistis use Triple Firaga and Triple Blizzaga respectivly while Selphie buff and heal. I recover the Limit Break option.
-Krysta : Still girl team, this time however I wasn't expecting his regular attack to do Stop so as a result only Selphie was immune via Auto-Haste, so she was the main Damage dealer with Triple Flare while Rinoa and Quistis were healing and buffing preparing for his Ultima. I recover the resurection option.
-Trauma : Took Squall, Irvine and Selphie. An interesting one, so apparently as long as even 1 Droma is here he gain a sort of auto-heal for almost 9000HP, the Dromas themselves aren't to threatning and go down easily with Squall and Irvine's physical attacks (with Tornado to Elemental Attack) and Selphie using Triple Tornado, Trauma's most dangerous attack is definitly Mega Pulse canon who does around 7000 damage and ignore Shell but this move is also a great occasion to use Limit Breaks to damage him. I recover saving ability.
-Red Giant : An easy one for once a mod doesn't remove his gimmick of being weak to Gravity XD. So just beefed up everyone Vitality, set protect cast Triple Demi 2 or 3 times and finish him off with Irvine's AP Shot. I recover the Command ability.
-Gargantua : Using Zell, Quistis and Rinoa first off we have to take off Lefty, Righty and Vysage no big deal a Triple Ultima will do the trick, Gargantua himself might be the second toughest of the 8 Guardian, mainly cause he can set Vit 0 on us, has Berserk and can use Vengeance yep this move again and his physical attacks are quite damaging, so just like Ultima weapon I putted Rinoa on Angel Wing as soon as I get the chance, so that he can't interrupt my offense while buffing/healing with Zell and Quistis.
-Tiamat : Using Zell, Quistis and Rinoa again, toughest of the 8 gardian but that's my fault I was focusing on Limit Break didn't know he could counter them with Ultima I realise that to late, so I switch strat mid battle using only Zell's Limit Break, outside of Ultima counter the most dangerous thing is he can now use Dark Flare whenever he wants and it's a 8000 damage in the face without Shell so yeah quite a damaging move.
-Catoblepas : Using Squall, Selphie and Irvine, well this guy only dangerous move his Heaven's Wrath just like Odin so my main Damage dealer was Irvine with Pulse Ammo and Squall using Darkside since he has low physical defense, Heaven's Wrath give a nice opportunity for using Limit Break due to the damage it does just have to be carefull in case it set Stop.
And so now for the big boy himself Omega Weapon, with he is definitly the toughest boss of the mod took me 4-5 tries to found a somewhat consistent strat against him and well show don't tell as they say so I record a fight :
https://www.youtube.com/watch?v=PSm1Ifm2yjE&feature=youtu.beSo basically he has all kind of nasty moves including Megido Flame, Light Pillar, Vengeance and Terra Break, Megido Flame doesn't deal 9998 damage thank god, seems to deal damage depending of characters max HP, Terra Break is the big one without Defend this move alone make the fight luck base, for Light Pillar Squall can actually survive it without Defend (with 232 Vit and Protect Squall take 8000 from Light Pillar) so basically :
-Squall here is my tank set Renew, Haste and Triple then putting him in Defend and he stays in Defend in case Terra Break, at least Omega can't use Megido Flame and/or Terra Break back to back (however he can use Vengeance follow by Terra Break it's rare but this is definitly the most dangerous thing that can happen in this fight) so Squall is safe to be on support when either of them is used, is role is to tank and resurrect the other after Terra Break.
-Quistis is the support, use Ray Bomb to inflict Vit 0 then assist Squall on support, using Renew on her and resurrecting Irvine when he die, also throw Aura Stone at Irvine (first time I use them cause yeah this is the strongest boss in the game normally so no holding back on that bastard XD).
-Irvine is the main damage dealer with Pulse Ammos, Pulse Ammos might be a little to strong with Vit 0, despite our dear XenoKyros labelling Irvine as garbage he can pull off ridiculous damage here Pulse Ammo deal 11000-12000 damage and up to around 24000 per Shots, I even got an extremely lucky turn where I pulled off 6 Shots and all them Crit that's over 130k here so much for Irvine being a garbage XD.
Got to admit I got lucky on certain part especially on the first Terra Break not Killing Quistis, this is honnestly the first time it ever happen usually she died (I did 5 tries and also did this fight using Zell instead of Irvine and on all of them this is really the only time I saw Quistis surviving Terra Break), and after the Ultima Omega Weapon didn't use anything that could have killed Irvine leaving Irvine a lot of turns to damage him. Showing my junction after the fight if anyone is interested.
Also you might want to nerf the Pulse Ammos a little for that fight tough XD.
Also I think Light Pillar as some damage overflow thing notice how at 3:40 on the video Irvine has 8000HP game tell you that Light Pillar has 3754 yet this killed Irvine regardless XD
EDIT : Well Ultimecia defeated decide to leave Irvine and Zell out for once so I took Squall, Quistis and Rinoa, Squall as a physical fighter with 100 Water to Elemental Attack, Quistis and Rinoa as mage, just make sure to have a Holy and Thundaga spells :
-Ultimecia : Basically just a warming I just try to survive waiting for my team to come up, once I got my team I set up them with Triple, Renew and Haste, then since she has a good Magic Defense and no good weakness to exploit I just use Squall's Darkside and some triple Meteor.
-Griever : Poor dude only did 3 actions (including the fix Schockwave Pulsar) before dying he is very weak to Holy so with Triple Holy Rinoa does over 40k and Quistis (who has less magic around 32k so over 70k per turn Squall just healing if needed, so yeah around 3 or 4 round of Quistis and Rinoa using Triple Holy and he is done, his Schockwave Pulsar does around 3000 with Shell.
-Ultimecia + Griever : Now Squall can get some good damage as she take a lot damage from Water element Squall can hit for 28-29k with Darkside, Rinoa around 27k with Triple Thundaga and Quistis 24k with Triple Thundaga so yeah almost 80k per round since I have by far the advantage in speed I manage to cut her tail before she even get the time to summon one of her little thing. Once her tail is off she acts a lot faster but she doesn't do anything dangerous except maybe Demi Schock but hey my Elixir are here for that.
-Final Ultimecia : Alright this one is a lot longer to kill than the 2 previous one, since she has no weakness to exploit I decided to just put Rinoa into Angel Wing and let her do damage (PS : I actually got an Apocalypse here who did 47k so that was nice XD), Squall can do damage with Darkside hitting for 14k and his Limit Break if he got the chance, Quistis is on support. She actually has her own version on Vengeance except it also dispel Angel Wing, but she only used it once in the entire fight so I just had to rebuff. She can still remove are spells, and something weird happened by the way at one point the game told me that she removed Quistis's Ultima, but it was Squall's Ultima that were remove, so that was weird and because Squall has become useless for dealing damage but that wasn't an issue cause this happen once the inferior part appear, at that point I just draw 31 Apocalypse with Quistis and was using her for dealing damage with Triple Apocalypse (1 Apocalypse hit for 10k with 207 Magic stat), while Rinoa was continuing her job, Ultimecia didn't get the time to use Apocalypse in fact after Drawing she losed time casting Flare.
Once the inferior part is gone at this point she is nearly done, she does however recover more than 20k between each of her monolog lines, but she also seem to become more trigger happy with Hell's Judgement so I use that as an opportunity to use Schockwave Pulsar who can deal at best around 45k on her
So yeah that was the Final Boss, so Griever and Ultimecia + Griever needs some more HP I think to accomodate for the fact they do have weaknesses, especially Griever Holy being one of the strongest spell in the game he suffers a lot from it, cause as of now they barely get the time to act. As for Final Ultimecia my only complains would be that she uses Flare a lot to much compare to her other spells (or maybe that was just luck in that case nevermind) and she should cast her Apocalypse right away instead of wasting time casting something else, otherwise Final Ultimecia is good she is a fun fight, she has enough HP to take a lot of punishment without making it to tedious which is what you would expect from a final boss and she does has some trick to spice the fight a little.
So I'm gonna retry the End of Disc 3/Beginning of Disc 4 bosses and then I think I will be done and will sum up my conclusions.