Modding 2012+ headlight housing

So I am attempting to build a full deep dish satoshi grill for my 2013 tacoma. Made a template before starting the build to make sure that I would have enough room for the grill to clear the headlight housing. I checked periodically to make sure I could proceed and everything lined up great..except for today. For some reason the added sides that I created touch the piece I labeled in yellow below:



My question is (please excuse the noob in me) :

Can I file/sand the part it rubs on without affecting the headlight in any way? Would I be able to without causing fogging/cloudiness/condensation from getting into the housing?

**I did some quick calculations but it would only be about 1/16" to 1/8" that would need to be removed.**

Side note - The area I labeled in red, what purpose does that serve?? There is nothing connected to it from the back and nothing is showing through to the front because the grille surround blocks it from being seen. Satoshi grilles would probably be more common if that wasn't there

Are there any replacement headlights without that piece I labeled in red?

As always, any info from TW members would be greatly appreciated