I have a few addendums to this question.
1. If I complete all of Season 0-1 and all of Season 1-1, am i forced into tier 3?
2. If I play between Seasons, do I gain skill and power feats if I only play 2 adventures?
3. When getting a scenario reward, such as "Draw a random blessing from the box", do we get to add that card to our deck, in addition to receiving a deck upgrade? I noticed that later adventures mention using this as an additional deck upgrade.