Tyler,
Because of my position in the company I cannot advise you on making alterations to the vehicle. I will only say that you should approach your solution no differently than you would approach your solution for a non-hybrid Yukon. You should also check with your dealer to confirm whether or not such a modification would have an impact on your warranty.
You should also expect that this will have a negative affect on your fuel economy, especially on highway. Roof racks are notorious for degrading the aerodynamic profile of a vehicle. This is the primary reason it is not offered on the Tahoe and Yukon Hybrids. It would require posting a lower FE sticker number.
Good luck with your choice!
Martin