From what I've read, you've done a great job with setting up your FastPasses (FP+). You've got a good mix of rides on there, and ones that often need FP+, so you've done well. Remember that once you use up your 3 FP+ for the day, you can jump back on the MyDisneyExperience (
MDE) app and get another one. Use it to your advantage.
I can't comment on the dining plan, as we always stay off property. But also know that Disney allows you to bring food and drink into the park, which most other places don't. So if you want to bring snacks, water bottles, etc...in, you can. Heck, we bring dinner for 5 in.
The only other advice I'll give you is to take your time and enjoy what you're doing. Don't get overwhelmed and don't try to rush around like crazy, for a few reasons. First, if you've never been, you really can't fully appreciate how large Disney is and how much walking you will be doing. My wife and I are extremely fit, and even we can get tired after a full day in the parks. It's a huge place. So don't wear yourselves out. Second, with only 5 days for all 4 parks, you're not going to see everything. You're just not. And that's perfectly OK. Look at the online maps before you go and find things you're interested in. If you have questions about certain rides or attractions, ask about them here. When you get to the parks, if you have questions, any cast member will be happy to help you. Yes, having a plan is very important to help maximize your time there, so I'm not at all saying not to have a plan. But it sounds like you've already got the framework mapped out. Honestly, I wouldn't worry too much about some of the "advanced level" planning you may see here in this forum. For your first visit, have a basic plan, go in with the understand you won't see everything, and be sure to just enjoy the things you do get to see.
Have an awesome trip!!