Putting their head down to request to be groomed is a sign of wanting to be the dominant one. If she gives in and grooms him then.
You need to properly bond them – you can’t just stick them together and not no what they do when you go to bed.
Bunny’s can get VERY Violent during bonding.
You should re-post your question in the bonding section. You will get a lot more help over there for this – as I’m no bonding expert either.
Did you do pre-bonding first?
How did the short dates go when you first introduced them while keeping them separate during pre-bonding?
Are they both spay/neutered?
Is there any humping? Chasing?
The food thing doesn’t really relate to alpha if he’s letting her eat first… my two just go to town eating at the same time – it could be she fought him off once at food time, that you didn’t see, any now he’s a bit wary of approaching when she’s eating. You’ll have to make sure that she isn’t eating too much and that he’s still getting enough.