DLR debuted a new version of F! earlier this summer. Now that the summer season is over, fireworks and F! are only being presented on weekends (Fri, Sat, and Sun). If you wanted to see either of those shows, make sure to plan for them on the weekend. Depending on your budget and how long you have, I would look into one of the F! dining packages.
If you're rope drop people, I would concentrate on doing as many rides as possible during the first couple of hours when lines are generally shorter. In this case, you may want to avoid starting in the park that has EMH/MM just so you aren't dealing with long (or potentially long) lines at opening. By mid-morning, the impacts of EMH/MM tend to be pretty minimal, so it's not as big a deal, but at opening it can impact the most popular attractions.
I haven't used MaxPass, but the FP system still worked pretty well. I think being able to make FP "reservations" with the app is nice, but it's not necessary (at this point). You still can't pick your time (that was my favorite part of
MDE). It does saves you the walk over to the FP machines. I don't know what kind of tickets you have, but I would probably get park hoppers rather than MaxPass. If you already have Park Hoppers, then I'd consider MaxPass.
Make sure you download the official
Disneyland App. It gives you current wait times, current FP return times, character locations and schedules, etc. It's not quite as powerful as MDE, but it's very useful.
If you know you want to eat at a specific locations and time, I would look into making a reservation now. It often possible to get prime dining reservations on short notice (dining packages are tougher, but regular reservations are often available for day of). I would especially consider making reservations for weekend days (usually when the crowds are the highest).
While not hugely popular, the Summer of Heroes event over in DCA is ending this Sunday (9/10). So if you wanted to check it out, you'll need to do that early in your trip. Otherwise, you should see Halloween starting to creep into both parks. HalloweenTime official starts on Friday, September 15 (Haunted Mansion and Space will be down until then). Parts of DCA are being decked out for Halloween for the first time, so that should be fun to see (some decor is already up according to recent photos of the parks).
Have a great trip!