The door buttons are different, if the wiring harness isn't the same and I'd be almost willing to be they're NOT, you're going to have problems. In the Envoy the memory seats are below the window switches, on the TB those buttons are around the door handle.
Other changes are the location of the 4x4 switch, rear wiper knob/switch, etc. If those harnesses are different or do not reach, you'll have another problem. As I think about it, the question arises if the inner door skin is the same, the outers are different and whether the same inner skin is used is 50-50. (I think they'll fit though, since the Rainier uses more of an Envoy body with TB interior). Actually, what you really may want to do for the upgraded interior is find a Bravada or Rainier....they have the nicer interior but with TB framing.