I do know a bit about AIDs (since I did do a large custom character dlc project), but I haven't dabbled in building an AID for a unique class model yet.
@TildeHat is the guy to go to for AID info. Editing any .bin file (like the AID files in the ROM) is a royal pain even if you know what you are doing since everything is pointer based. Add one extra byte and you break the entire file. Hence why I do all my edits with dlc, since I can just make new files in the dlc cia instead of repointing stuff to make room.