To hum canceling with another single coil it has to be RQRP relative to that particular single coil..
Fender and SD pickups are, I believe and for example, wound in opposite directions to begin with. Therefore you may get away with a "regular" SD single coil in the middle, I don't know for sure.
Also, you may not get the results you want with, say,, Fender neck and bridge and a SD RWRP in the middle.
With an HSH setup it'll have to work with the correct coils in the humbuckers. I don't know which ones those are, but you may find if you want to use one set of coils you'll need a RWRP single coil, but with the other set you need a regular single coil.
Someone more knowledgeable than me needed here.