It would be a bit of a challenge.
The models have different blend shape names, slightly different body controllers, and different fine-tune parameters that make them visually grow at the same rate. For example, a check that happens in certain encounters is it asks if a player’s belly is bigger than 1.5m in diameter. The model (internally Anya) has a different scale that comes from the sum of different blend shapes than the model named Ivan.
If someone wanted to add a new actor they’d need to add a new controlling script and play through the game to make sure things are still sane. If the game says, “You look like you’re ready to burst,” when the player is barely showing a pudge then it’s annoying. I had this problem at the start of making the game.
If someone had a model and animations I could see adding it in like a YCH, but solving for all possible models would be too much effort for me.