So, will it then be possible to insert any mesh?

I have downloaded a lot of models from various sites to use with different poser and video creation software such as Source Filmmaker.

Who wants to have a good time with Harley Quinn?

Well, yes, but it wont be as easy as just hitting "replace". The models have breast, vaginal, anal, mouth interaction zones so your models will need those too. Also their kinematics have to be at least very similar.

Copy that, I am fully prepared to learn and make this happen.

If you want to trial and error load that non cloth body.ma from resource pack and try exchanging saiko's low poly mesh with your own. Then try filemake that and running in game, that would be a good starting point.

Except that the game crashes when you start it using even the same mesh with one poly moved...

Nah, not if you do it right

I would love to be enlightened!