Enhancement/Evo - blue treasures.
IMO regarding enhancements/evolution.
If you evolve your enhancements to max before evolving your target card and then stack that 3 times for each evolution u do get a stronger Final Form.
in regards to blue treasures from what i read on other forums and my experience they are rarer drops than the treasures (meaning they dont appear on the quest as a potential drop [that gold square u see with the question mark at the bottom of the quests]) and so they are harder to get because u cant grind specifically for them. I am currently at the tablet completing all the treasures before. What i found most helpful with this was finding all the other treasures first saving the yellow and blue for the end (not sure why yellow but for some reason yellow key was really hard to get and keep) then get yellow and then camp out check the game every 5-10 minutes and attack anyone with a blue key after that its just really all luck whether u'll find someone u can beat that unluckily stumbled on a blue key before completion.
Hope that helped.