Luna is a solo bun, so I don’t know much about bonding, but I’ve read on other posts that some have tried rebonding by starting over at step 1. Maybe if they are put in a neutral space again and put through the whole process again, he will not act so dominant anymore?

Bunnies can’t be properly bonded whilst they still have hormones flying around (before neutering and spaying) so they’ll need to be bonded properly once all involved have been neutered and have recovered.

You’ll need to have the female spayed for health reasons. 80-90% of unsprayed females will get uterine cancer by age 5. If you want to bond him with the other male, he will need to be neutered first. Which ever pair you want to bond – will need a good 4 weeks to recover from the surgery, and for their hormones to do away. Then – you can start bonding. In the mean time – you will have to keep them separate. Unfixed rabbits can get hormonal, aggressive, and hurt each other very badly.
When you are ready to start bonding, write back and ask for more advice. Read up on prebonding techniques too. It isn’t a simple matter of tossing one rabbit in with another as a cage mate. It can take as little as 2 weeks to bond, or months. I have heard of a 3-year attempt. Myself – I bonded 2 pairs in 2 and 4 weeks respectively, and a third pair in 8 months. If you start putting bunnies in eachother’s cage without bonding properly, you will have injured bunnies with grudges.
Try giving the lonely bunny a stuffy. two of my buns have stuffies, and they love them to bits. Give him lots of attention. Unfortunately – he will have to be on his own until there is a suitable recovered fixed bunny for him to bond with.