The rex fur is recessive, so all the babies would just have normal fur. You'll probably just get chestnuts for color too (unless the rex is a chinchilla, squirrel, frosty, ermine, white, Californian, seal, sable point, self chin, sable, smoke pearl, sallander or other chinchilla/himi/shaded based color). They'd be okay meat rabbits, not as good as pure chinchilla, but better than pure rex.