[quote=@FlitterFaux]
Hold the phone. [i]I[/i] could theoretically make missions for other players?

How does that work? Does one act as the missions GM? What are the limits/restrictions?
[/quote]

Since you created the mission, most of the time you would be the GM for that mission specifically. Your title is Mission Antagonist and the only limits you have are the normal ones any other GM would have.