Snowy has been jumping on top of Bella (kitten) and holding her by the nape.

My mentor says it's a dominance thing. He's trying to show his dominace over her.
Well, I thought, O.K. but then I glance over another time and Bella's doing the same thing to him!

last night, I slept in the foster room, with the aliens. Snowy cried his song outside, then I heard Bella (she is starting to sound like a velociraptor) and Snowy, obviously upset, was starting to take it out on Bella. They know they're mad, but can't discern who to be mad at. I got worried for Bella, but it calmed down.

This whole pattern is becoming apparent every time I open the foster room for business.

Everyone's upset, but thankfully, everyone calms down eventually (even the fosters).

I think you have normal cat politics on your hands, unless you hear shreaking.