The other members have pretty much covered everything, but I just have a couple of small tips.
Getting Ajax to eat (so he can poop) asap is paramount, so if all you can tempt him with is treats, feed him treats.
I would try to put some folded up fleece in his temporary tiny prison. Having something soft to stretch out on for the first day or so seems to make our shelter buns more comfy after snipping.
And finally, if your vet doesn’t already, I would insist on bringing home some liquid metcam painkiller. I don’t care what some “experts” say about it not being necessary after a neuter. A neutered bun has just had his skin sliced open, internal organs cut, and was then sewn up. He will feel pain after a neuter even if he’s extremely good at hiding it due to evolutionary reasons. He needs pain meds for a few days, if not for humane reasons, then simply because a bunny not in pain eats and toilets better.
So make a stink about it if you must – shed a crocodile tear or two – but get that little vial of metacam.
And finally, smooches. Lots and lots of headrubs, ear pets, and smooches right on his adorable twitchy nose. (((Easy neuter, Ajax bunbun)))