What you choose for his companion will be up to you. If you get a dove or finch, definitely he'll have another bird in the cage with him even though they won't be together. If you get a male or female gambel's quail, they'll stick together (eat together and move together). If you get a male...
By this point, there should be enough indication that it's a male or female - if it is all brown on the face, it's a female, but if it has black feathers the face, then it's a male. Show us a picture if you'd like and we'll try to help you. As for a companion, it is still a little early but...
I raise them too. When they hatch, they need a higher protein diet (~30%). In the wild, chicks feed mainly on insects and they start incorporating more vegetation in their diet as they get older. As adults, their diet is opposite from what it was as chicks - meaning adults prefer more veggies...