Cleared the phase 2 bosses as well. The special 5th boss seems just slightly harder than the special 5th boss from phase 1: I managed to do it using only 2 Tea Sets, helper squad wasn't even necessary. Power of each of my squads is between 130k and 140k. (139k debuff squad, 133k trigger squad, 133k counter squad, 131k solar squad. Trigger and counter squads dealt most damage.)