As to this part of your question, that can a a crap shoot. Most of us find that our greys' have their favorite, but tolerate and develop some type of relationship with the rest of the family. This isn't always the case though. Getting a weaned, fledged baby from a breeder would probably help with that, though I'm no expert. Those of us who have rehomed know that our birds carry memories and associations (negative and positive) from their previous owner's homes that can affect their relationship with your family members.
There is a lot to think about in the other members' responses, good information. Good luck!