I won't be able to complete the set even after finishing all the quests and getting a lot of the random scrolls around my city. I will be at least 2 rounds away from getting the last building for my set at the end of the event. and when you figure 40 flags at 25 scrolls per flag, that's about 2000 scrolls short. Glad I haven't spent any cash lately. Won't happen ever again.@schadenfreude it is possible to get the full set without using diamonds in my opinion. I only need another 9 staffs to complete the set and haven't spent any diamonds on currency. Between the remaining quests, login bonus and hourly drops I should get enough currency to finish the set.
I do agree that reducing the event currency has made the recent events harder to complete the set/evolving building. I think that if you finish all of the quests that you should be guaranteed to complete the set/evolving building with or without the ashen phoenix/stash outpost.