I appreciate the info very much, which is why I asked! I didn't think about the fading aspect. Going back, it looks like I misread what Xpel's website said about UV protection. It was in regards to the film itself, not the protection it does or doesn't provide. Found a FAQ section and it said UV is indeed allowed to pass through the film, however, as long as a coating/wax doesn't have high levels of petroleum distillates in it, it can be applied to the film.
My headlights are $2,000 EACH from Ford, so I've got to do what I can to keep them looking new. I'll still get the film, just have to work on the UV part now.