Might've been the Bios. My computer BIOS got corrupted, and I resetted the breakers, and did the CMOS trick, and it didn't work. Got a friend to fix my Bios, and it worked fine.

• I still haven't figured out what the direct cause was, but which surfaces can I absolutely NOT let my motherboard touch? I was building on top of the Gigabyte case (like they did on the newegg tutorial) - Nothing metal.
  
• Is it okay to lay the motherboard on a wooden table (the one pictured above)? Yes
  
• Will the motherboard short if it touches ANY of the metal casing of my NZXT Phantom? When first placing it in, is it okay that the standoffs are a little off and touching some other part of the bottom of the motherboard than the holes? Not sure.
  
• What is the best way to grip the motherboard when placing it into the case? Should I put the motherboard first into the case before the PSU? With your hands, and yes.
  

I'd go with the anti-static. I built my computer on a wooden table on a wooden floor and touched the case each time before I touched a part just for safety.