We've been to Universal several times. Our first trip our kids were 1 1/2, 8, 11, and 13yo. The kids all liked it and there are truly things for all ages.
We're not a big fan of Back to the Future. I feel like I'm being thrown around, but will go on the ride if I'm with someone who wants to ride.
We liked the Street Breakz show a lot--very entertaining. Blues Brothers isn't our thing quite as much.
My kids has never been scared of Jaws, even when my youngest was at a fearful stage (I say stage because he is a true daredevil, but did have a year that he was scared of things--he was 3yo then). For some reason Jaws didn't scare him, but Spiderman did. Go figure!
Jimmy Neutron is fun, but something is off on that ride (I think the movement doesn't exactly match the picture) and I always feel a bit sick after it. I do take ginger capsules to help with that. BTW, I'm fine on Mission:Space. I do JN each visit at least once, though.
I LOVE Men in Black. I can ride it again and again for hours.
We all like the Horror Makeup Show. We've always sat right up front and my youngest is always somehow made fun of in the show. His very first time at that show he was around 3 and he was playing with some coins during the show and the emcee brought everyones attention to how he wasn't even paying attention to the show.
Pteranadon Flyers is one person per seat, but 2 seats are hooked together. That ride scares me a little and my DH won't ride it. What a weenie he is!
Stay dry on One Fish, Two Fish? Uh, sure, whatever you want to believe!

We are talking sprinkles, not soaking wet.
Be careful of the fountain. You REALLY can get wet there. My youngest loves it and we usually just bring extra clothes for him.
I don't think that kids under 40" can go on Spiderman at all, unless they have changed the height restriction.
You older son will like Mummy Coaster if he likes Space Mt. It's a good ride!
Shrek is a fun show--so much better than the 3D shows at WDW. Don't miss it!
Any other questions, ask away!