I personally would not bother with the dining package for Frozen. You have a lot of dining and package experiences booked already and this way you can be more flexible on when you go to the show. We went in early August and entered the Frozen show queue only about 40 or so minutes in advance and were within the first 20 people for the mezzanine. We chose seats 3 rows back so the bar wouldn't be our view and were right in the center. It was perfect and not stressful at all.
I saw that you already purchased MaxPass - we loved it! I'd make a list of your priority rides for each park, aim for those first in the day, and then be flexible. Sometimes it takes a little for all the rides to come on-line at park opening so just be prepared to move to the next and come back. To give you an example, one day we had planned to do this order: BTMM, Pirates, Haunted, Splash. Every single one was closed at rope drop! No biggie though, it all worked out perfectly in the end.
Cars Land in DCA is one our most favorite places. Be there at dusk and they play the song they play in the movie and turn on all the lights. Ride RSR at night at least once - for some reason, it is extra cool at night. FPs for rides around 8:00 pm were being distributed around 12:00pm when we were there a few weeks ago. One other thing to be aware is Soarin' is down to one screen right now. As such, the lines are long and FP is running out early in the day. Using MaxPass, I'd snag either a RSR or Guardian's FP as soon as you enter the park and then walk on to Soarin' at rope drop. Actually - I just remembered you are staying on-site. Plan to ride Soarin during EMH.