Here's what I got so far:
000000006bff1e383c584e48= ui_upscale\purple_guy.png
000000007519b4019bf0ae34 = ui_upscale\moogle.png
00000000023139f0a7afe217 = ui_upscale\save.png
00000000020f6f462a6c78de = ui_upscale\tonberry.png
00000000674ff67b2a5c490f = ui_upscale\firebirdy.png
000000004a7329da2da6e84d = ui_upscale\cactuar.png
0000000026800ae51447f3eb = ui_upscale\big_statue_man.png
00000000c37657bc28a1af6d = ui_upscale\silver_summon.png
#00000000ccb0c441669d523d = ui_upscale\gray_summon.png
000000001df8a8bc1b09c63f = ui_upscale\ifrit.png
If I find the rest, I'll let you know (I think they may appear during Chocobo Mode).
Some of the screenshots that occur a lot during Angeal/Tseng aren't upscaled and they're a bit random so I'll keep a list of what I find for those).
Right now I'm in Nibelheim, here's some updates:
For some reason, I found this texture in the files but I'm unsure whether this sign is (I found 4 in the main village), if anyone knows where this is in the game, please let me know:
I just discovered a texture error (I'll try to edit the door texture later to fix this):
I think the directory looks good although I have a few concerns. I find it very hard to read, I wonder if you can reduce the transparency?
Also, why does it say Shinra was founded in 1902? Is this based on canon?
If not, I would remove it since while I think adding flavor text is necessary sometimes, if it adds non-canon info, it's too much on the iffy side for me.