MacBook Pro won't boot from USB installer or go into recovery. Tried everything
I would add this as a comment, but I don’t have enough reputation...

Did you use cmd+R for internet recovery?

The reason I ask is that I’m currently going through a similar problem with my 2011 MacBook Pro. My bootable USB installer failed when attempting a clean install. I tried internet recovery using cmd+R, but that failed too.

By using the advice in this post by boris42 to use cmd+opt+R, I was able to enter internet recovery mode and I am currently installing Lion (the only option available), and will upgrade further from there.