I had the same problem and could not tell where it was originating. I siliconed and lubed so much stuff and the squeek went away temporarily every time. I finally wrapped some stick-on velcro (soft half) around the hood latch bar. It is the part on/under the hood that fits into the latch mechanism when the hood closes. That connection is the source of your squeek - I'll bet money on it!

This has been the only fail-safe remedy.

Good Luck!