Festival of the Lion King is a great show in Animal Kingdom, would recommend that. The main parade in Magic Kingdom, Festival of Fantasy, is also amazing! For the parades and the firework shows, you want to get a seat along the parade route/near the castle quite a while before they start, at least 30mins, as people start waiting for them at least an hour before and it can be hard to get a good view.
Magic Kingdom is the main park, you'll want at least a day for that. The don't-miss rides are (IMO): Space Mountain, Big Thunder Mountain, 7 Dwarves Mine Train, it's a small world, Pirates of the Caribbean and Jungle Cruise. The Enchanted Tiki Room is also great, it's a short animatronic show.
Hollywood studios also has great rides, like Rock'n'rollercoaster, Star Tours, Tower of Terror and The Great Movie ride.
I'd recommend getting Disney tickets linked to a My Disney Experience account (you can link once you buy the tickets), then you can create and organise restaurant reservations and ride fastpasses online or on an app, it was so useful for us when we went. And you can get magic bands when you're there and use them instead of hard tickets, they're electronic wristbands.