It seems they are getting along well (whoohoo, you are lucky as even bunnies who pick each other out, can fight back when the new bunny is put in the original bunny's territory)
So there are a few things going on here. Circling does mean he wants to mate, and honking is very low pitched and quiet, so you would really have to listen for it. But even if he wasn't, circling still means he wants to mate with her. And part of the spraying too is to tell any OTHER potential male rabbits (even though there aren't any) to stay away from his gal.
And the territorial dominance display also can be a message directly to her to reinforce that he's the king. He may not want to fight for it as he doesn't sound aggressive, but it may be his passive way of trying to get the message across.
A bonding process not only helps them get used to each other, but also helps them get used to each other in each others space - slowly, so they don't freak out with marking too much (though some temporary excessive marking is normal)
One thing to watch for is things can change once she feels secure and at home. She may express her dominance through aggression. (also though most likely he is spraying, females can too, but it is definitely less likely, since she is spayed .)
Okay, so what do you do now? I am very glad it is has gotten better, but you unfortunately may have to restrict their freedom a bit until this has fully settled down.
Unfortunately in their own hutch, there isn't much you can do accept wait it out. It doesn't sound like they are not littertrained, just doing the territorial marking.
As far as parts of your home goes, I would get a few xpens and block off your bunnies' freedom to places that are unacceptable for marking,. You can let them back in, but as soon as the spraying starts, he gets put back to the "allowed" area for a few hours, or the next day. Depending on how insistant he is, this may need to be repeated for weeks.
Also, when you clean their urine/spray, what do you use? They might be trying to respray over it, depending on how strongly scented the cleaner is.
Some great options to get rid of urine smell are: Vinegar & Water(50/50) and Nature's Miracle but definitely do a test when using Nature's Miracle, because it can miscolor some fabrics. (of course if you have hardwood floors, you can't let it sit,) Now this should help get rid of the smell all together, not just cover it, which can encourage marking.
However, they still may feel the need to mark some to get their scent out and feel secure as they claim their place. One of our members, Anistark, (I think it was her), anyway, one of our members had success with spreading their bunny's scent by taking a damp washcloth and rubbing her bunny with it, and then rubbing the area that the bunny likes to mark.
I have heard this works on other animals, so though I haven't tried it with bunnies, it sure can't hurt. The worst thing you have is a semi damp bunny.
Keep us updated on how things work. I wish there was one set answer for every problem. It's always more complex.