I bonded my 2 year old neutered male with a 2 month old baby girl successfully. When it was time for her spay, I kept them separate but in the same room so she could heal for 2 weeks then they had a few bunny dates before being put back together again. They have been together a year now and are quite bonded. We had the boy 2 years before we got his bond-mate and he was and still is extremely bonded to us. He will choose us over his bond-mate most the time.
The downside is that she never really bonded with her humans, though we lavished attention on her. Now that I have a new little girl as a third (and am just now starting bunny dates) I plan to keep her separate until after she is spayed so she can fully bond with us first. Also, I anticipate it taking longer to bond a third bunny plus female to female. My boy bunny and the new baby already get along pretty good during their bunny dates. I don’t think I can bond an un-spayed female with a spayed female. Does are just too territorial.