Is it possible to make this with less sugar?

Yes, of course you can reduce the amount of sugar you use. You can use just about anything you'd like to sweeten your vinegar/fruit mixture. It's the vinegar doing the preservation, so as long as you use one of at least 5-6% acidity, and take care to sterilize your container- you are fine reducing the sugar level to suit your taste. If you have particularly sweet fruit, you can even eliminate it completely and rely on just the fructose to provide a counter to the vinegar.

Definitely. I think drinks like this are sweetened to the drinker's taste buds. :)