Well, you can crimp some connectors on to put them in the old plug if you want to be neat, but if as you say they are soldered, I assume they would be soldered to the balance pot, so shouldn't be an issue.
ok, so I was curious and looked. The Ibanez EHBs (all of them) use the 3EMP3LD preamp module (and a few other related parts). The pickups go to two plugs on the back of the balance board (3EMV5S), one 2 pin plug for each pickup. The balance board connects to the volume board and it in turn goes to the preamp. There is no soldering to be done on any of those boards. If you don't want to make a plug you can cut the old pickups off and connect the new pickup outputs to the old plugs and plug them back in, but obviously that can be done out of the bass, so it would be pretty risk free.