Umm, I don't have JA yet but I just want to know if you can or how you can put npcs in an MP map like (not just with cheats or with cheats) make them spawn when you first load the map.
The easiest way is to use the NPC_spawner entity and create a custom npc. I used that method in the Wayland_CTF map Darth T-Bone and I will be releasing soon.