Here is my intended solution to "Requiem in A Minor":
First lemming climb-bombs, somewhere below the exit platform, although this bomb has to be rather precise. Next two lemmings are also made climbers. First climber bashes, next is turned, builds to the exit platform, turns, and mines at a rather precise point. Basher is made a floater (not sure if this is required), and blocks almost immediately upon hitting the floor. Miner should mine into the blocker and turn, and free the crowd. One of the crowd needs to build to the other part of the tunnel before the miner fully breaches the floor (why you only need 70% -- if I put some steel there, the level could require 95%).
I could make another somewhat deeper water trap, like the one on the left, but deep enough to catch a basher that goes directly into the wall.