So I street parked my 2012 Outlander and when I got back it was like the attached picture.

I just purchase a replacement lower grille on Ebay, anyone know of a link or guide to replacing the lower grille? Do I need to remove the whole bumper to replace the grille?

 

See section 51-4 of the service manual. Probably other locations in the manual where it shows to to disassemble it as well.

Looks like it is secured by screws behind it in the engine bay

Download it from the sticky'd thread

 

That's bad crack there should be clips or you could get some mobile repairer to repair that bumper