You can a copy of the FSM and parts fiche at
http://colorado4wheel.com/manuals/Jeep/KJ/ . The FSM has wiring diagrams that may or may not help. I honestly do not know if DCJ ever sold a kit or if you can put the parts together from the parts fiche.
As far as swapping seats. Yes you can swap in the seats from probably any KJ assuming of course that you can find heated seat(s) in acceptable condition. That said as I recall from discussions over on the CRD side of the forum you will have to swap over the airbag sensor(s) from your current seats to the replacement seats. I assume you want to keep the leather seat which may significantly narrow the range of used seats although you could swap your current leather seat covers to the new seats.
Given all the work involved I suggest you give serious consideration to after market seat heater kits which are readily available for under $100 per seat in either a fit over style (fits on the outside of your existing seat cover) or fit inside (would require removal and re-installation of you existing seat cover). I've done OEM seat cover installs and it's not a big deal if you want to go with the fit inside option (just removal and install of a bunch of "hog" rings); alternatively a car upholstery place would probably do the job for like 1 hour labor per seat if you brought the seat to them.