It's entirely doable, but I think it's actually less work to reconfigure the pins at the amplifier connectors instead of trying to re-wire the entertainment connector. There is a great write up on this at
https://www.dieselplace.com/threads/diy-lux-nav-install.40437/, although he doesn't add the new wiring to split the D-pillar speakers off of the rear door channels. I have the factory service manuals and so I used the wiring diagrams in them to rewire everything to LUX specs.
One more thing, the LUX amp that I purchased needed reprogrammed with a Tech2, because the D-pillar channels weren't turned on when I got it. Fortunately, I have a Tech2 and so I was able to reprogram it to turn them on. Also, the LUX amplifiers are tuned in their programming for the the cabin configuration. So without a Tech2 you can't reprogram it for crew cab vs Tahoe vs Suburban vs H2 cabins and it won't sound it's best if that is not set correctly. If your amp came from a Yukon Denali or Escalade that were short wheel base, then it should be good, but if not it will need reprogramming to sound best.