Well i have realized something. there are several companions that people want. But if they give a side quest or involved in a promotion quest probably will not be a companions. example i think a lot of people want gortez on their crew but Lucky jacks promotion you have to talk to gortez. what if someone does the quest late has gortez on their crew where are they going to talk to him? in a tavern cellar? (that might work.) but still i do not think companions who give or involved in side quests will be companions.