You can't cook the burgers and chicken ahead for good results. Just figure it will take 20 minutes per burger batch, about 30 per chicken. If you are doing at home, you can roast the chicken in the oven, then immediately onto the grill.

I would use Polish sausage or kielbasa instead of hotdogs. Taste better, more popular.

1 burger per person, your choice 3 per pound or 4 per pound
1 piece of chicken per person (a quarter is 2 pieces
1 pound sausages per 6
Rolls and trimmings, see the sandwich page, do 2/3 the amount for 100

3 gallons potato salad,
2 gallons slaw
2-3 gallons another (green, pasta, beans, etc, your choice)
1 pound chips per 12, 1 pint dip or salsa per pound