I'm pretty sure you could swap the upper and lowers with no real problems. I've seen bagged escalades with DJM tubular uppers. They make a torsion bar lower control arm also but if u scrap the torsions, not really needed.
The mounting locations I think are universal on all the trucks. Only thing is you have to check to see if the spindles will accept the cailpers....the Yukons run larger brakes then the pick up trucks I believe.
I also think you may have a upper coil perch as well, if not you'll need to fab up upper mounts for the shockwaves.
You may be able to get away with a tubular upper and shockwaves, just depends on how low u wanna get.