My horse lives with two llamas (different, but similar) and they get along fine. They aren't best buddies but they're enough to keep my horse happy living by herself.
The one slight issue is that my horse is dominant over them (and she's completely not dominant to other horses, ever) so making sure they get food can be an issue at times. I just make sure they have food in more places than there are animals which seems to work well for everyone.
Fabio - 13 year old Arab/QH gelding
Hazel - 14 year old Angora goat
Atticus - 4 year old LaMancha/Alpine cross goat
Rest peacefully, Lacey.