I had a lone baby chick that was brutally bullied by all the adults (7 adults) and I had to separate him from them. I raised him indoors and he turned into a nice rooster. He got free roam of our yard because he was never accepted...I still don't understand the rejection. But I think based on that experience a lone chick might fare well given proper attention. As for Bantams and Buff Orpingtons that's what I have now and I love 'em! They get along great too. I originally started with 3 Buff Orps., 3 Rhode Island Reds and 3 Peking Ducks. I added a few weeks later 6 unknown breed Bantams from the local feed store, 6 Cochins and have continued to add more Bantams ( 28 Auricana/Americauna? Bantams). I now have a total of over 50, maybe 60 fowl. The pertinent point is that they can get along fine. I have recently added a large Americauna rooster and the Bantams beat him up so I believe it should be noted to introduce them young. In my opinion though you should probably have 2 chicks minimum for social reasons but as I said I raised a lone chick before.