On a 96 I think you're looking at a rear wheel only setup. It should just be a matter of finding the right sensor that will work with your system.
The rear sensor on the differential is super easy to swap. One screw and a plug. The fronts do require pulling the wheels, calipers and rotors off (easy enough, but lots of heavy parts if you're not built for that -- I'm not).
I used
http://www.fordparts.com/ to look at the sensors for different years (slight pain, but not too bad compared to pulling the rotors off and splicing cables). What you want is a part that will work the the control unit you have and fit the axle(s) you have. If you get too modern you start running into the ESP tone ring issues, at which point you might as well buy modified axles from someone like ujoint. The older stuff however, can, for the most part, be pieced together with existing components, at least as far as I can tell.
Oh, on the front end the van seemed to use the same connectors, but of the incorrect gender. I ended up fixing up the van side to make an future sensor swaps easy.
A cheap scan tool that will read ABS codes is probably worth its cost here. It's not like anyone but a seriously specialized shop is likely to help you with this.
Thanks for the interest BTW! I hoped this would be of value to someone sooner or later. Since I really don't have any skin in this game other than making my own van work better, I figured the time spent sharing this is an easy choice for me to make.