I finally have the material attribute working here, but now the issue of a part file having multiple local materials, and the wrong one being the primary, has arisen.
As many of you know, if you create a wave link, the material of the parent body of the wave link, will become a local material in the file the link was created. If you create a few wave linked bodies for reference, and then create the actual part geometry, and forget to explicitly assign it a material, the part file will make one of the wave related materials the primary. Then, we end up with the wrong material populating the drawing file, and boom, we have a part made of the wrong material. This would be bad 
Anotehr issue, is when you have multiple local materials, you will get prompted to select one during part load, and if its an assembly, with a lot of parts, the user may not know what part it is refering to, and click ok, inadvertantly changing something they shouldn't. In the past, I have seen parts get made with the wrong material due to this.
Also running Part Cleanup, with the "Delete All Materials" toggled on, does not delete materials, at least in my testing. I will contact GTAC on this one.
So, how do other companies deal with making sure there is only 1 material, within the NX part file? I know there are attributes for MaterialMultipleAssigned, MaterialMissingAssignments, and MaterialPreferred. Is there any way to use those to help the situation? Of simply create a limit of one local material per NX model?
I'm sure large companies have a checking system, but this industry does not have that luxury, time and manpower is crucial with very short timelines. Automating, and making things 'idiot proof' (for lack of a better term) are crucial.