No need to convert the original tilesets, the maps will work using the MV tilesets as long as you limited yourself to the original tilesets.
Faces: The generator-style is completely different. If you used generator faces it will be better to simply redo them in the MV generator.
As for other resources: It depends. A 150% rescale always has a quality loss, so not everything was rescaled and sometimes people just changed to different resources.
If you can give a specification of what resources you want to rescale it would help much.