In case anyone has a similar question and also cannot seem to find the answer, here is an email I recieved from one of the head NASA tech guys as well as a link to the official regulations book which he references.
"Harnesses: The only 4 point harness systems we allow are those that carry an “FIA B-xxx.T/98" certification. I could not find any info on the system you mentioned that states if they meet this requirement. I would also like to stress that we do not like the 4 point systems and may be banning them altogether in the future. We would much rather you run a 5 or 6 point system. If your Corbeau seats are FIA rated then they should have a cutout for the sub belt(s), so installing a 6 point system should not be a problem. For the shoulder belts you would need some type of harness bar. It is not acceptable to mount them to the rear seatbelt anchors. The distance is too far and the belts can stretch too much at that distance."
"Seats: For mounting the seat please see the following sections in our CCR 11.4.12 and 15.16.2. I've attached the CCR for you. Some manufacturers sell kits to mount it to the stock seat locations which is acceptable for HPDE. If you want to use the stock belts with the Corbeau seats you can do so, provided they meet the following requirement: The lap and shoulder belt must stay in contact with you. What I mean by this is that some of the race seats are very deep and the lap belt does not actually come in contact with the occupant, it just sits on top of the seat. This is not acceptable. As long as your seat allows the belt to stay in contact with you, you are good to go."http://www.nasaproracing.com/rules/ccr.pdf
Hope this helps anyone who's in the same boat as I was!