So you're really shooting against the clock there.

That was my feeling hahaha you nailed it, i had to shoot as many people i could before the night!!

Do you use a tripod with 1.8/2F or is it generally okay to hold by hand but still get faces in focus?

I never use a tripod :P i usually put the shutter speed at a1/125 or more and play with the ISO to get enought light