I can partially answer your question.

The KJ CRD and gasser transmission coolers are in different locations; the CRD is in the bottom of the AC condenser. The factory tow pkg on the CRD is simply the addition of a Mopar receiver hitch; a round trailer wiring female plug (forget how many wires it has and simply don't know if that includes a brake wire but I can say the factory pkg does not include a brake controller); and a male wiring adapter plug to go from the common flat trailer lighting plug to the round plug that's part of the factory tow pkg.

Adding wiring is apparently somewhat complicated depending on whether or not you have the EVIC; whether or not you want to add a brake controller; and of course whether or not you want a flat plug or round one at the rear of the vehicle. I'll let others that know lots more than me on the wiring to provide comments.

FYI if you are towing heavy addition of an aux tranny cooler is a good idea. There are multiple posts on that topic but PM or email me if you want direct links.