With a baby bond, you don’t know if it’s one that will fall apart (common) or stay intact (less common) once the baby becomes hormonal. I always err on the side of caution and recommend owners to keep complete separation and not try bonding until both rabbits are fixed. Ultimately, if a bond is not going to work, it won’t be because you didn’t start sessions pre-neuter– it’ll be because of rabbit personality incompatibility, and a rabbit’s personality isn’t truly “present” until after spay/neuter recovery and generally an older age (+6mo).

What you can do is the pre-bonding measures, and I believe this can be helpful. This means swapping litterboxes, toys, pens (if plausible), and that way they have a good amount of exposure to living in each other’s scent. You can also do side-by-side living, as long as neither rabbit begins displaying aggression. Injuries can still happen through bars, so if that is the case, you can do side-by-side with a gap in between. This allows visual and scent exposure without the risk of physical injuries.

We have bonding process information here once everybun is ready: https://binkybunny.com/infocategory/bonding/

If you want the baby boy rabbit I would start with pre bonding like said, but I would wait until he is neutered. ( after he is neutered you need to wait a month of you could end up with baby bunnies) I would do this to make sure the bond is lifetime.