i think maybe you can take it this way: the profile the projection of that feature on Datum A B and C must within .002, thus if any of the dimension of 0.135 or 0.730 goes wrong, it won't reach the requirement!!!
i think the dimension 0.135 comes to play for the requirement to datum C.
for the other questions, maybe we need more info, such as what the part is use for,etc.