I think you can't reverse the procedure.
Anyway player may don't want to max girl skill or slot, since everything will be reset.
Like you see, after upgrade my Anemone will get skill lv reduse to 1.
And according to the last popular vote, any rarity girls will set as priority target for this new system.
So any 2★ - 4★ girls that got the prize will be in for sure.
I... don't really remember who win it, but seem Maria and Cyclamen will be 100% in this system