They can be mixed on the same satellite, just not the same line, or through the node or anything of that nature. In this instance, would have one port dedicated to the 722K, and then the other two ports into a DPP44, and that to the Node and then integrator(I might have those backwards as I have limited knowledge on the SJ install). Will most certainly need all three ports and a switch to be put into use though, for the 7 tuners he is wishing to use.
I only had 2 lines coming into my house. The installer ran 2 lines from the dish to the solo node, then one line from solo node into my house. Then the 3rd line from the dish she ran to the integrator. She tied the integrator to the solo node and then used the 2nd line going into the house to connect to the other end of the integrator. The line coming off the integrator goes directly to the Super Joey. She then used a tap inside the house on the line coming from the solo node for the Hopper and regular Joey. Hope that makes sense! PM me if you have any questions and I'll try to help.