Thanks everyone! BF and I are still so thrilled that Genever and Dorothy are getting along well. They don't play together all that much, but when they do it's chasing and (play) fighting, so sometimes we're not sure if they are annoyed with each other or not. But I think if they didn't like each other, they would not tolerate sleeping so close.
You're right, G-cat does look annoyed in those pics, but I think she was annoyed at me waking her up with the camera.
I'm still perplexed by the grooming thing though. It's still the same. Dot will go up to G-cat and stick her head in her face for a cleaning. Genever only cleans her head/face. And Dot still never grooms Genever (or us). Sometimes it's Genever who goes up to Dot to start face-grooming, but usually it's Dot who goes up to G-cat. I guess it doesn't really mean anything, but there are other instances where it's clear Dot is boss. So... who knows. I should stop trying to analyze it and just enjoy the kitty love!!
Merlin will go up to Shareena and stick his face up to be washed. I always thought it was more of a submissive behavior, not showing who's boss. (Shareena is very definitely alpha cat around here).