Re: H/S/S w/ RWRP in Middle-will it work?
If you're talking about a Seymour Duncan pickup, yes, it will be in phase. (Assuming green to ground, black to hot.) If its any other brand, its hard to say. There's no standardization in absolute phase of pickups.
If you hook it up, and it is out-of-phase, just reverse its hot and ground wires.