In MP mission role selection, does "nobody" mean that bot team-mates are impossible?
In some multiplayer missions I've downloaded, the Role Selection screen sometimes fills all the roles with "nobody" instead of the more common "AI" when I start the mission. Does this mean that the mission author did not code any AI for your team-mates and there is no way to get bots on your team?
There are no AIs because the mission author did not set any waypoints/behaviour to AIs and so it is mostly pointless to have team-mates AIs in the mission.
However you can unpbo the mission and edit description.ext - you must change DisableAI= 1 to DisableAI= 0 then team-mates AIs will be available but keep in mind you should set AIs behaviour/scoring in editor.