Hi! You should be able to put him out in the barn as soon as he's weened. Make sure that he has hay or straw for bedding and a draft free place in the barn. I would highly reccomend getting another goat as they are flock animals and do much better with a friend. You may also want to have him...
I have always had luck mixing breeds that I raised together. If you get chicks and look into docile breeds you should have no problem. I have Cochins, Wyendottes, Brahmas & Orpingtons and they all get along really well. Good luck!