Actually the bandit spotter and skillinfo i know need updated but i'm unaware which files can error the game. There's a few other files i see that were updated and i'm unsure of if UOTiara uses them.
I actually encourage people to open up pack files themselves and see how things like 'turn blue when Mana Shield is on' or 'No lightning bolt time-out' works. If you can sort out the major files/mods of interest, and prevent the client from crashing, then you could probably get most of your major files edited and placed before UOTiara even finishes downloading. May take some practice to remember what files go where/do what though.
I've been out of the loop since I stopped playing Mabi regularly, so I don't exactly know what the bandit spotter uses, but I know that an outdated skillinfo shouldn't crash, and any changes to it should be minimal. 'If it doesn't crash, it's okay to keep' is what I usually follow xD
Besides, it's pretty easy to figure out what's causing crashes when there's small updates like character cards/gachapons. (If there was any crashing)