You have a CAN bus vehicle so SOMETIMES it's as easy as going in and enabling things with a dealer level computer, HOWEVER...
1. Dual zone climate requires ripping out the dash, the door structure is different between single and dual zone; you can't just change a module or program something and voila there it is lol. I have two LX's, did you actually change the temp door (to allow for split temperatures) or did you just plug in a DZ module?
2. Installing the power sliding glass physically is easy. You need to figure out if there is harness already there for both the rear (by the glass) and in the dash (to install a switch). If both ends of harness are there, and there is an empty spot in the fusebox/TIPM, it may be that simple (expect it not to be).
3. Steering wheel controls will depend on whether your clockspring has the requisite pins for the plugs off the steering wheel buttons. If it doesn't you will need to replace the clockspring so they have matching pins.
The CAN systems are similar between your Ram and a Magnum with the exception of BUS speed.