2006, GMC, Yukon XL, V8, 5.3L; FFV

Removing the rear HVAC unit to open up more space in the rear of my vehicle. Looking for tips on how best to pinch/plug the ac/coolant lines after removal. Or tips on removal from anybody who has done this before.

I've never heard of this being done. You'll probably want to take it to a certified automotive AC technician.

One option could be to cap the AC lines up under the hood, then remove the rest as needed.

For the coolant, I'd suggest you loop the coolant supply line into the return line under the hood, then remove the rest as needed.

Use Swagelok style fittings to grip pipes cut in engine compartment leading to rear unit. Local shop sourced fittings to cap off rear air in our 99 sub cause of a/c leak in rear unit. Not cost effective to fix leak. Swagelok fittings are tightened to a specific amount to seal.