First of all, don't worry about a thing. You're gonna have a great time. I once planned a trip with 30 minutes notice in mid summer. Living 9 hours away from WDW, my wife and I decided about the trip at 5pm, left at 5:30pm and drove half way. Arrived late morning the next day. What did I learn that might be of service?
1) Go with your instincts when it comes to planning which park on which days. You have hoppers so if you run into a crowd just hop on out of there. Seems like MK is usually the problem, but YMMV. As for Disney Springs, it is an enjoyable shopping experience if you're into that sort of thing. We typically spend an evening there during any WDW trip
2) Why not go to EMH hours? If you're night owls (like us) it's always a good chance to linger and take things at a slower pace, and hopefully catch a few rides with shorter lines. I tend to avoid EMH mornings because it's just too darn early after all these years. Been there, done that, and got the t-shirt. For all things there is a season, and my season of early EMHs is over for the most part.
3) Pandora is very well themed. Flight of Passage is probably the best ride on property. If you get a chance to swing by Pandora after dark it is worth doing so. I'll let other folks sell you on the food. Rivers of Light (night time show at AK) is a very chill experience. Don't go into it looking for spectacle and you just may be glad you saw it.
4) I hate to break it to you, but several things you may remember at DHS are no more. It's still a fun park though. We spend partial days there. Over at Epcot be sure to catch Soarin'. The new film is nice. This probably sound cuckoo but if you are at Epcot and trying to rest for a little while check out the Pixar/Disney Short Film Festival. No new shorts but the presentation is pleasant.
5) As for FPs, you will get a surprising number of headliner FPs. Oh, and account for the fact that some attractions that formerly did not have long queues now practically require an FP (ie Haunted Mansion)
6) I have always found dining pretty easy to handle on short notice except for at the most crowded times. There have been several occasions I have gotten lunch ADRs for Be Our Guest a day before the date, once even on the same day. It just requires a bit more checking and work on your app. One more recent QS option I recommend is the Geyser Point Bar and Grill at Wilderness Lodge. It's a beautiful setting and a delicious meal. We had lunch there but I also hear good things about their breakfast.
Most of all, R-E-L-A-X... it's going to be a blast. Those short-notice trips are the best IMO