You might need to request that the tech use a larger splitter than he otherwise would so you have three open ports to plug in the unused coax cables every room active. If the installer won't do it, who cares, it will take you about 30 seconds. HoTat2 noted you're supposed to have terminators on the unused ports, but if you want to have to active lines in rooms without receivers so you can easily move them, you either need to put the terminators on the unused wall ports (and remember to swap them around when you move receivers) or just don't worry about it.
Issues with lack of terminators are mostly theoretical, it certainly isn't the sort of thing where you're guaranteed or even likely to have problems. Sort of like grounding, really. You "should" do it if you want to do things exactly right, but many people get along just fine without it. If you ever have problems you can add terminators to see if it helps, but I'd bet heavily they make no difference
What I'd suggest is to have him plug in the two HRs on one side of the SWM16, using a 2 way splitter, and the Genie, clients, and unused rooms on the other side using an 8 way splitter (I assume it will be the clients you move around, not the HRs) That should create the most efficient setup since the clients need to talk to the Genie and won't have to cross the SWM16's internal bridge which adds a bit of extra loss. So long as you don't have any really long runs (over 150 feet or more) from the SWM16, this will be fine.
SL5, PI-6S, SA-6AL, 3xSWM16; 21 H20-100, 1 H20-600, 7 H24-700/AM21