Problem with body parts morphing oddly when animating

[Sidereel]

I installed a bunch of custom followers. They have their own skeleton, and it was causing severe fps drops, like from 60 capped to 15 whenever I was around them. I read a few threads that said to replace the skeleton with the xp32 skeleton you normally use, because it might be causing problems with HDt physics. I did that, and the fps drops stopped. But, now whenever I engage those custom followers in any of the sexlab animations, their bodies morph weirdly.

Like their breasts turn into 3 foot long points, or they go concave into their bodies, and their butts turn into points. So I figured I needed to give them a body mesh that supported hdt, so I built one in bodyslide and replaced their bodies. It helped somewhat, but their bodies still slightly morph into weird positions when engaging in animations.

Is there a fix for this, or do i have to choose between misshapen bodies or fps drops?