Can the piece outlined in yellow be removed alone? I've taken out several bolts and it still feels like it's stuck to the headlight/grille assemblies.

 

Sounds like you might want to get your hands on a factory assembly manual...very handy when taking things apart and putting them back together!

The part you've circled is the upper portion of the core support, which is a single large piece bolted to the frame. The fenders, grills and headlight all attach to it, which is probably why it feels like it's stuck to the headlight/grill assemblies.

 

That is part of the core support. It does not come off without drilling out the spot welds.