According to the description for the Rupes pads section on AGO "Rupes 100 mm (4 inch) Foam Pads are designed to be used with a 3 inch hook and loop backing plate", so in theory I would say yes if your backing plate is a hook and loop but I aint no expert.
Yes the pad will work as long as the pad will fit.
I've seen guys take sheets of foam, cut circles out, glue them to whatever backing plate they can come up with and stick em on a rotary and buff with them so anything can be done.