When you do something of that kind of magnitude , you have a lot of thins that you need to keep in mind.
First, if you have a different rear axle setup for your truck you need to make sure that it has the right gear ratio. It has to have the SAME gearing that you have now, unless you change the front gears at the same time to match the rears. The brakes have to be adaptable, the control arm mounts and spring and shock mounts all have to be remade for the axle housing, and you have to figure out how to make the driveline work on the new diff.
I think you might have your work cut out for you to make everything work for you. You might just be better off finding a high mileage GV, maybe with a bad engine, and put the engine, transmission and transfer case in to it. Then you could easily build the GV.
Unfortunately nobody that I'm aware of makes a locker of any kind that will even come close to working in the XL-7. Sorry. I think you are better off leaving the thing relatively stock and build something else with the Suzuki nameplate on it.