Not the original guy, but down 32%, for a point of comparison:

1) Amazing, like being a decade and a half younger

2) Not before, planning one in the next couple months, but I use skinfold and impedance and they say I've dropped from about 48% to ~20% as I've dropped from 272 to 186, lean mass seems maybe 5kg lower than I started with? Less lean mass loss than I expected.

3) Weight bearing exercise and medium-high protein intake (>80g/d)

4) Per above, starting BMI 37.9 -> ending BMI 25.9