2wd cossie rear hubs yes + brakes!!
2wd cossie front hubs, yes but will need different TCA's as if you use 3 door ones as they have a TAPER fitting joint(in TCA), as opposed to castle nut.
I am sure that is the way round it is done it myself.
Front cossie 2wd brakes will fit STRAIGHT on a non cossie 2wd hub by the way, just got to tap the lug hole that's all, done that as well, major difference in braking dept!!.2wd stub axles do fit 4wd as far as I know but not 100% certain.
tabetha