It's definitely doable.
Do you folks ride coasters?
A couple things to consider:
1. The water rides at Universal are much, much more aggressive at getting guests wet than their Disney counterparts. Assume that riding one is going to get you about as wet as jumping into a swimming pool wearing whatever you have on. Ponchos will not work. If your party isn't capable of dressing in quickly-drying clothing and/or you're not willing or capable of bringing a full change of clothes/socks/shoes for everybody, skip the water rides.
2. Universal is far stricter than Disney in its allowing guests to bring bags with them on rides. Whereas you can pretty much get away with sitting a small backpack at your feet on Rock n' Rollercoaster, Universal's employees will all but pat you down before letting you ride Hulk or Rip Ride Rockit to make sure you don't have a wallet in your pocket. Both the Potter rides require that everything you have with you be stowed in a locker as well, which eats up time. If you don't have someone in your party who is going to stay with the stroller or whatever to watch the bags, it might be easier to just plan on everyone just taking what they can fit in their own pockets.
3. Either Rip Ride Rockit or Escape from Gringotts will break down at some point during your one day at the park. Probably both. Just anticipate this and work around it. They'll re-open again in a few hours. Probably.
4. Like at Disney, not all restaurants at Universal are created equal. Unlike Disney, a lot of restaurants at Universal in the same price range are significantly better than others. Circus McGurkus Cafe Stoo-Pendous, I'm looking at you. You'll probably want to avoid any counter service place not at Springfield, Jurassic Park, or either of the Potter sections. If you had two days to work with I'd recommend Mythos, but you don't.
5. Skip the shows. All of them. They're all lame. If the Blues Brothers or one of the Potter street shows is going, feel free and stop for a minute, but none of the live entertainment offerings at Universal right now is worth, say, another go on Mummy or Men in Black.