The first two are defensible but the devil is in the details. How do you combine U1, U2 & U3? How do you combine stress in (W+P1) and (U1+U2+U3)? Are D4, D5 & D6 ranges or amplitudes? Do you count cycles in (D4+D5+D6)?
I have no comment on the third. I don't think an owner of a B31.3 facility would care to reference a nuclear code.