How about a green iced tea, not sweetened, with bottles of Italian syrup in lemon, mango, and raspberry to add in? Usual packets of sweeteners, of course...

Float sliced strawberries and orange, lime, and lemon slices in your big clear lemonade container. Frozen concentrate is best quality. You might use limeade or one of the tropical blends as one of the cans- each 12 ounce can makes a quart and a half.

Instead of soda, consider a sparkling punch, see the punch thread. The apricot-pineapple with ginger ale is eternally popular. Again, fruit juices can be frozen into rings or blocks to add both flavor and color. Less expensive than soda, too.

Now amounts; 3 gallons each would make sure everyone gets what they want, some leftovers.