I bought the Hydrotools through the wall skimmer complete set, which came with a return fitting.
I noted the outside threads on the back side looked like they might fit the Intex 1-1/2" hose fittings. Checked it out, and yes they work! I don't know if any of the other brands of return fittings have the same thread, I suspect they do.
I'm refilling the pool now, and will be bringing one of the pumps out to finish the opening clean-up. I'll post later with a report on leakage, if any.