Types of Mobs in Solo & Team Missions

I was wondering if anybody figured out how what types of mobs appear in solo and team missions? There are some solo mission where I find nothing but Fixer, Crat and Agents in a mission. Other missions I find another three dominate mob professions in a mission. Has anybody figured out how to tweak the mission settings so you get more mobs of a certain type? What about mobs and bosses in team missions? Have people been able to tweak that? Does the keeper of the mission influence the mob typs in missions?