I thought you could connect the client with a short coax stub to a DECA, using ethernet from there? Not supported, but others have reported it works. You could even run a short ethernet stub to a wireless bridge and not need to run any wire at all, though considering the pool house isn't even built yet, it is presumably not a problem to run wire.
Though with OP talking about originally wanting a Genie and H25 there, running a SWM output seems like the best solution. I guess either he's thinking about having a couple TVs and watching sports by the pool, or this pool house is really more of a guest house with a living room and a bedroom or two.