Why do we think that print sharpness is influenced by paper emulsion? The resolution limit of standard enlarging paper is far beyond human detection.
I'll also doubt that there is a distinguishable difference between an 8x10 contact print and a 4x5 enlarged to 8x10. As long as the 4x5 lens delivers 34 lp/mm or better, you won't be able to see a difference without optical aids.