As for having to have 2 goats thats not a given rule of thumb. As long as he has someone or something to play with ( You or your Horses ) he should be fine. Just give him a little more attention
I dont know about that. I wouldn't do it though. With all the slop from the pigs your just begging for foot rot problems along with other health problems.
I would just put him in with the horse's and forget about it.
I personally haven't had goats with pigs but I've heard some horror stories from a couple of other people who said they wouldn't put pigs with ANY other farm animal; including one girl who said her pig attacked her goat and did serious bodily injury to it.
A wether should have a good grass hay. Alfalfa can cause UC problems so I'd stay away from that except as an occasional treat - just like the feed.
If you have pasture available let him browse that. He'll love it and it'll save you some cost on hay. Just make sure you have no poisonous plants and that your fences are water proof. er... goat proof.