What should I do with our guineapig?

Ok, here's another question on Beano ( my brothers guineapig). If you've read my other questions you should know that he can no longer be put with my rabbit now that she is spayed cause she has turned alot more territoial (false advertising on the spaying me thinks �_�!). Anyway, rabbit is indoors now and guineapig is left outside alone in the hutch. One we are wanting to get another cage for the guineapig so he can be indoors too (do pigs squeal alot at night cause he will be in my bedroom ontop of the rabbits cage?). And Two, we are thinking whether we should get him a friend. Now he's been with 3 different female nonspayed rabbits and no fighting, but never a guineapig... do you think we should try to get an already spayed/neutered pig (dont want to pay for it at the moment) or do you think he will be ok with a normal pig or do you think we should give it a miss?? I really want Beano to be happy and I feel bad that I hardly ever go out to see him (especially in the winter whether).