Once again, I thank you both for helping me. I've since finished editing almost everything regarding the other banks that are not able to be compiled with CastleFynn, to my satisfaction, and have successfully changed the pointers. In the end, yes, I did change five or so squishy tiles (I changed the item icon, the 'e' meant for S[il][e][nc] and made [nc] into a standalone, among other things upon abw's suggestions). For example, due to items not really needing an item icon, I replaced it with a more useful squishy tile (like [in]). I've even better organised the tiles.
My only wish is for the boxes as big as the ones in FF1 and 3 (have the battle message box at the bottom go from 16 char limit to 22, enemy name box 8 to 10, and "attack" box 4 to 6). Although space is very limited as you've said, the battle messages and "attack" ones would not pose too much of a problem because I can put some of the names in another bank, like how Chaos did with the last 5 enemy names (I have 8 in total placed at the end of the battle message bank, with spaces to spare). Perhaps there's a way to remove the unused songs to make more space?
I have one thing left I need help on. In FF1, I've found the strings correlating to what is said at the end of battle("Monsters defeated" or "[Lead player's name] and co. defeated"). Each actually two messages linked into one, as you know. By editing 0x2D970 in FF1 JPN from 04 to 09 (or anything higher than 08, it seems), I'm able to take out the "fetching" of the lead player's name so I can make full use of the 22 spaces and edit it to make it something like "Party's been wiped out".
Is there a way to do the same with FF2 with Firion's name? Instead of "[Whatever you named Firion] lost.", I would like to make full use of the 16 spaces in message 24 of the Battle Messages bank (something like "Party's wiped out").