Sounds like your switch to a 70 and up water pump has you on the right track, as long as you have the matching 70 and up timing cover that goes with it. Then the common aftermarket balancer is the last piece of the puzzle (along with a different radiator which it sounds like you are already planning on). When you order the balancer, order for a 1970 and up.
The radiator is what sent me down this path. Didn't like my options for drivers side upper and lower hoses. So I have the new radiator and water pump. Guess since my assumption was wrong I will order the timing cover and balancer. If marks line up.