My personal current to-do list, and help is welcomed:
BRSTM to NUS3Bank script
Finish offline NUS3Bank inserter/appender
Add extra SFX clips to voice/SFX NUS3Banks, then load through animcmd/sound.bin files
Add and display song titles, source game, and descriptions for additional song slots (involves sound/config/bgm_property.mpb, ui/message/sound.msbt, and param/ui/ui_sound_db.bin)
Finish patch resource modifier to load any custom file with proper flags
GUI for managing music files, My Music settings, and song titles, etc.
Update Smash Custom Music website to generate sound.msbt file based off template lists
To be done by someone:
Convert models to editable format, modify, then reinsert (use
RTB's maxscript as a reference)
Finish subroutine hash table for PSA related stuff (use
dantarion's site and
Sammi Husky's tool as current reference)
Figure out stage collision data
Animations (.omo files)
GUI for texture editing (for now needs texconv2.exe, but hoping to move to non-SDK tools)
Documentation at OpenSA Wiki I have a lot of clarifying to do on stuff, since I've mainly been writing scripts with no looking back, just to make sure I can get things working. If anyone has any specific questions, let me know and I'll answer as well as I can.
Added to OP.