a) Trail camp is where 90% of hikers stay. Consultation Lake is more out of the way, off the main trail. Mostly your choice.
b) Leave the tent up, with access to the critters -- or they might chew through. Or better, if you are heading home same day, at least collapse the tent,maybe roll it up so it's ready to take home.
c) Three liters from Trail Camp is the general guideline. One for the distance up to Trail Crest, one for the summit and back, #3 back at Trail camp for the descent. 4L is probably not too much, but make sure you drink all of one through the switchbacks.
I have left the last one at Trail Crest, hidden, and retrieved it for the descent. Saves carrying two lbs up to the summit and back.