I have looked multiple times, but can't tell, are you supposed to do the additional rewards as well as the epilogues when playing the mini-campaign? Because it seems kind of crazy that the rebels are getting from 3-4 xp every mission!

Did you read the text in the Additional Rewards section?

"If playing this mission as a side mission..." It only applies when played as a side mission, not when played as a minicampaign story mission.

Thanks