1 YES very nice.
2 Me, I would use a db meter and set all the channels to the same volume from you seating position, others will help with crossover frequencies, i would guess about 80. Or if your new HTR has one of those auto setup deals try that then adjust from there.
3 No it should be fine they shouldn't play much of the same frequencies anyway ( nice sub) [Y]
4 Not familiar with Rf prices but to me it sounds like a good deal.
Others will be along with other opinions and help, Welcome you did good.