The designers wanted to make the upgrade as hard as possible, so you need the seats, the memory module that sits under the driver's seat, the driver's window switch assembly, some wiring, and then you need to pay a dealer to configure the BCM to control it all. If the truck wasn't built at the factory with the option, they didn't want it installed later.
That said, you can install a power seat and use just the local movement control on the side of the seat with a minor amount of wiring that has been discussed in some threads here and on trailvoy. And the heaters can also be controlled manually. Takes some electrical experience, since it's not plug and play.