I noticed while the car is on jack stand, the BMC brace was pushing on the BMC too tight. I guess the chassis has too much flex. After removing the BMC brace, the pedal seems to feel firmer, but still too soft unlike before.
I don't see any drop in fluid level in reservoir. There is no visible leak under BMC I could tell from looking from above.
I bled hours upon hours on this sucker. I did the pump and hold method. But it seems like there is always some tiny foamy bubbles in the one caliper I rebuild. The tiny bubbles should not cause the pedal to the floor. However there is no weeping of brake fluid from the piston dust boots.