first I would put a block of wood under the pedal to limit its travel to the normal range (not a dealbreaker but it keeps the cups in their normal worn range of travel in the bore). not sure why the rear bleeding wont go down, I would try it on both of the rear bleeders (which you have likely already did) & if no change then possibly crack the T hose fitting back there & repeat. are you running a prop valve of any kind?