I just dropped a JX set in a Geddy body. The pickups fit great, but beware! The control cavity in mine doesn't have enough room (depth) for the battery. This is one of the solderless sets and the "buss" you plug the wires into is on the bottom of the pot, thus making the pots "deeper" than average. I've had people tell me the MIJ bodies are thinner than MIA's and Squires, but I can't confirm or deny that.
If the JV's have the normal side-lugs that you solder the wires on you should be in good shape. I, on the other hand, am pulling out the router for a battery box.
Good Luck!