What Growler says we can vouch for.
We notice from time to time, that Yogi seems to want to play predator/prey with him being the predator and one of the 2 girls being prey.
This doesn't go over too well with either one of them, but Mrg seems to be more tolerant and will put up with a little bit of rough housing before the hissing starts........sometimes she is the instigator too. BB just doesn't tolerate any of it. She just lets out a scream that would waken the dead.
And if it happens in the wee hours of the morning, it's one rude awakening.
There always seems to be territorial issues with who is going to sleep where. It does get into a hissy match once in a while.
When you have been used to dogs and suddenly you are getting involved with cats, it can be a real education really fast.........it appears though, that your 2 are starting to function like normal cats and that's good.