Good luck:
#1: You don't have to I like to take a gel right before the start, then again around mile 5-6. You will not run out of glycogen in a half but I still take fuel as I posted.
#2: Band-Aid work for me, you can also use glide or some Vaseline and that will take care of the nips! Cotton is not the best type of shirt, tech shirt.
#3 I like a banana with some peanut butter, but the goldern rule is don't do anything knew on race day, do what you have been doing for your long runs!