with my experience I would keep the buck seperate from all the does,,there will be fighting..except when you know who you want to breed you can put them in a seperate breeding cage/run. Other than that you would be better to keep the buck beside them but seperated if you can.
my hens and ducks were ok together as long as they had plenty of space to roam around,,if they're too confined you may get fighting there as well. My 2 goats are in a paddock during the day with the others during the day,but I do find it sometimes dangerous when they get an urge to run,buck and play around all frisky! The hens try to get out of their way,but this year I'm making a seperate run only for the chickens. Rabbits seem to become ill easier when they live in with chickens ,,,I've always kept rabbits in hutches with runs but not in with the ducks or hens anymore,,,as I found that they would pick up bacterial infections easier.

Goats will not be good watch dogs. They are on the "prefered menu" list of every predator.

Some people will let chickens free range inside their rabbit barn to clean up any rabbit pellets / food the rabbits waste. This isn't necessarily bad...but it can be. For instance...rabbits carry coccidia. They will not give it the chickens...it does not cross that way. But the chickens can give it to the rabbits. When the chickens are scratching through the rabbit poo on the ground, they could get it on their feet. At night when the chickens fly up onto the rabbit cages to roost...the poo / bacteria fall back down on the rabbits...hence potentially infecting the rabbits making them sick!

I agree with beeliz...keep as many animals separate as possible. You do not have to get fanatical about it. We have free range chickens that scratch and feed in the goat pasture. I even have a couple that will not go into the coop at night...they roost in the barn over top the goats. Just make sure you keep the goat feed troughs and water buckets cleaned out.

Keeping doe & buck rabbits together is a bad idea no matter how you try to justify it. If they do get along for a time period...when the doe has her kits...the buck will kill them. Another doe will kill them as well. Rabbits are very territorial. They need to be housed in separate pens...period. Very rarely does it work in a community pen. When it does...they need to be in a large area like a chicken run. This way each rabbit can have their own little corner of the run as "their territory."

Hope this helps...

Brian

Good info. Thanks. I guess I'll keep the rabbits in separate cages, in their own area of the housing, someplace secluded.