First, ignore post #2. There are plenty of well informed adults who post on this forum. I'd recommend looking at the
www.velomine.com wheels offerings. You can actually get 27" wheels with a flip / flop hub there. As to the BB, are you needing to buy cranks? If so, you'll need a BB to match the crank as well as the frame BB threading (Italian) and width (probably 70mm).