I'm not sure about bunnies who have bred together, as I've never bred rabbits before, or anything else for that matter.
Seems to me it should make little difference. Yes, spaying/neuturingdoes help, but I've bonded bunnies where only one was fixed and theother not and it went fine. Also, from what I understand, other bunnieshere who aren't fixed seem to be bonded as well.
However, I see you're point, as in, does breding effect this. Sorry that I couldn't answer.