The Hopper 3 takes over the Hybrid LNB when it's plugged into port #1 so no other receiver can be connected to the same Hybrid LNB. If you want a Hopper 3 then it's got to have it's own dish, at least until Dish comes out with a compatible switch.
According to Vivek the Wally will work with the Hybrid LNB, in fact he said that you can put up to 16 Wally's on a single Hybrid LNBF with the proper splitters.
I did an install today with a HWS, a SuperJoey and 2 Joeys using the Hybrid LNB, a duo hub and a Hybrid tap. No splitters or integrators necessary. It was very clean.