Yeah, I think it makes sense now. I was thinking it was going to be possible to remove the bumper skin without taking anything else off, but it looks like the whole bumper assembly is coming out to get to that set of clips. The stuff I already removed is all the atachment points other than the bumper beam, allowing the entire assembly to slide out... we'll see tonight.
I'll write up a how-to if I ever figure out the "right" way to remove this thing