Some general advice to add.
You have a good amount of time, but you still will not be able to do everything! For each park, prioritise what’s important to you. What would your family like to do? 5 or 6 must-dos plus some “nice-to-dos” is a good start.
A character meal is a good way to meet characters without spending time waiting in the parks. CHef Mickey’s has Mickey, Minnie, Donald, Goofy and Pluto. You can meet 3 or 4 of them elsewhere but that’s the only place to meet them all together.
You will have the added problem of some serious jet lag issues, with no way of knowing how it will affect you, so I would not be planning to rope drop. If you manage it, that’s an added bonus. With the night time shows, either plan a late start to the day, maybe swim first, or a break mid-day. We’re from the UK, plus my family are not early risers, so we never rope drop. Your family may be different, but that jet lag may catch you unawares.
I split the parks in 2 typically. For MK - Fantasyland and Tomorrowland, then Frontierland, Liberty Square and Adventure land. For Epcot I prefer to do half of FutureWorld and half of World Showcase one day and the rest the other. It mixes up rides with strolling around nicely, especially when you don’t really know how the kids like it. Pick 2 or 3 countries to explore fully.
For DHS it’s tricky. I’ve been maybe 5 times and we still take more than a day. The shows can be tricky to schedule, and the Star Wars stuff can take a while. As someone who likes Star Wars but not a huge fan or nerd (unlike say DH), I still loved seeing March of the First Order etc. And spent over an hour in the Launch Bay. Jedi Training is another thing altogether, we are past that stage but it needs either rope drop or an early breakfast to get signed up. If you want to do the rides, Star Wars and even one of the shows you will need at least a day. If you want to see both Fantasmic (you really should!) and the SW fireworks then use 2 days but maybe one late start, or a break. The shows are good fun, I love Indy. The “half day” view is often from those who have seen the shows many times, as they haven’t changed much. If you want to see them all, or even 2 or 3 of them, you will need 2 days.
Avoid the pitfall of making your plans and not leaving time to just enjoy the parks. There’s so much to see, street performers to watch, ice creams to eat, characters to meet (many of them are not scheduled at set times so you can’t include them in the plans as such).
Above all, use the plans to get a feel of where things are and how long things take. Then be prepared to deviate from them if necessary. Kids want to Splash in the fountains? Great, grab a coffee and sit down for half an hour. Dapper Dans singing in Town Square? Go listen, they’re fab. Allow time to skip down MS and pose in front of the castle. Enjoy the bustle of Harambe in AK. I put plenty of breaks in my plans, 30 to 60 minutes every couple of hours. That’s my style. If you’re a “go go go” family then make the plans and fill them with as much as possible. Whatever works for your family is the “right” way for you!
And ask lots of questions here. Do you have a subscription? If so, you can make your personalised plans and publish them here so people can offer advice. There’s lots of experience on this forum, and there’s no such thing as a stupid question either!
If you haven’t already got one, I would suggest getting a guidebook to start. Find out about the parks and get a feel for what you’d like to do. Don’t forget there’s lots to do outside the parks for relaxation and excitement.