1. There's threads in the photography board about fireworks photos. Just take a little time and go back through.
2. Dark ride photos are tricky. The lower the f stop, the better, but even then there's more to it.
For Disney pictures in general, I've found that the 18-55 kit lens is a good start. I keep it on most of the time. The only time I use my telephoto lens (I have a 55-250) is when I want to take pictures across the lagoon in Epcot. Other than that, the 18-55 is what I use.
Just keep in mind, the darker things are, the more prone to camera shake you'll be.
As far as my tips for fireworks, you'll need a decent tripod (or trashcan, wall, whatever you can use that your camera won't move), a shutter release and you have to put the camera in Manual and set it to Bulb.
I did some research before I went and tried it the first time, and I just started learning by trial and error. With the 4th of July coming up, that's a good time to go out and practice. Sure, you're not going to know the fireworks pattern, but it's still practice for learning how to anticipate bursts and such. That said, if you're going to shoot HEA, Illuminations or Star Wars fireworks, you'll want to know what shots you want to get and know where they are in the show.