Will the Model 1070 have enough juice for my HT? I will have Paradigm Reference Studio 40 (for RF and LF), and the Paradigm CC-570 for the Center. All are stated to be 8 ohm impedance. I do not know what I will put in the back...

I ran Paradigm Studio 60's and a Studio CC (both v2, not the v3's that I'm guessing you have) with a Model 1050 (which if anything had slightly less power than the 1070) and was pretty pleased with the results - and that was without a sub. If you get a sub, you can unload some of the power-hungry low frequency work from the receiver's amps and put it on the powered sub's amp instead. I did eventually add a separate amp, but that was mainly to let me slowly migrate to true separates.