I found some cool avatar assets last night, simple svgs/pngs arranged in a way that all fits together & have a total of 266.4 trillion combinations, woah.
Compared to Snapchat's Bitmoji of 1.999 septillion combinations it's not so big
Avatar creator preview
Since all the assets are simple and generalised, assembling avatar combinations has a very low conflict/bad display rate, only a few adjustments have to be made to stop stuff looking messed up.
When companies make more advanced/realistic looking avatar creators, it quickly requires a huge increase in technology, but also makes their use cases sky high.
However, since this system is a simplistic/2d system, creating scenes where a user's avatar is in a different position or scenario isn't too much of a technological step up, as simple changes like facial expressions (mouth, eyebrows, eyes change state) and head rotation attached to a body will suffice.