I was going to go this exact same route in my Squier VM PJ. I really needed a bridge pup that didn't buzz, and already had the Fender 62RI pup.
Luckily for me I couldn't get just the bridge model J pup, so turned to the Fender Super 55 jack pup. This is quit a thick sounding jazz pup and I love it. It's solid enough to use on its own, but blends well with the fender P pup. It's not quite as growly as the stock Squier pup! but good enough to add that extra growl to the P tone.
I now have a Fralin in at the neck position now, but to be honest I don't really hear much difference between the two. Again, the super 55 blends in really well with that as well.
Just another option possibly worth think it about.
SQUIER VM PJ 3TSB | SQUIER CV Jazz Bass with Wizard 74's | SQUIER CV 60's P Bass with Fralin pup| Spirit XZ-2 | MarkBass F1 LE| Schroeder 1212L |Zoom B3 |MBCM#62 Classic Vibe Club #46