Here is pretty much all you need to know regards the pickup sizing in MIM jazz basses.
Fender's final word on different pickups in MIM Jazz?
Short form is prior to 2001 standard MIM J basses had 2 of the same size pickups. Deluxe models,
prior to 2001, at least the examples I've seen, had the neck and bridge length pickups found in MIA basses, which is what is found in all MIM basses built from 2001 forward. As for any MIM reissue J's, I would imagine they would have whatever pickups the bass they are a copy of had but I don't know for sure as I've never owned a reissue Fender of any kind.
One of the areas where Fender saves money on standard MIM basses is pickups, they are serviceable, but I find them to be a bit anemic. No prob though since any standard J bass set will fit the newer MIM basses, there is an unlimited selection of pickups to replace the stock units with. All the MIM J control plates I've seen were loaded with 250K CTS pots and an 047 brown disk cap.
I don't know the origin of the jack but I've never had one fail on me.
As for bridges, the aftermarket is lousy with Fender specific five screw top loading bridges so like pickups, shop til you drop. You can replace the plated brass saddles with threaded rod saddles for around $15.00 or you can get really crazy and spend more for a bridge than the bass cost new off the rack, or anywhere between those two end points, or you can leave the bridge alone and just play it for a while.
I really like MIM j basses because I can get a good used one for less than four hundred bucks, drop in some nice pickups and some fancy hardware, have the neck edges rolled and a top shelf fret job, even refinish it and still have less in it than what I'd spend for a new MIA standard J.