>>537914529
I've dusted off my brain, and managed to find the assets in the APK itself.

Don't have the time now to go through everything carefully but here's an imgur with the full body portraits (only proper KOF characters) and half body portraits (KOF chars, generics and enemies), plus some stuff I found worth including.

https://imgur.com/a/XvHBnU3

I also found the sprites and the spine (animated portrait parts) files, but I wouldn't know how to get them working.

Things I noticed: Oswald has Spine and Half body portraits, but no full body portrait. He's the only main KOF character like this, that I can tell.
There's these little pets and companions you can put in your team, and it's full of deep cuts I enjoy. Cool Guy, King's waitresses, Lin's Hisoku friends, the fat women, the cameramen, Athena's friend, etc. Amusingly a llama with Iori's hair.

There's a full body portrait for a guy labeled "Bread", I assume it's the "player character"

Barring Athena having a 98 and a Schoolgirl version, there seem to be no year-specific versions for anyone. No one from non-mainline KOFs either. Lily does appear in her Maximum Impact design as one of those companions, but she also had that design in a background in XIII.

Instead of low-tier versions of, like, Choi from 94, the bad gacha rolls now get you the generic enemies from KOFAS, who you can put in your team.