Here are a couple of things to factor in your decision: 1) You mentioned other character meals but none with Mickey, Donald, Minnie. If they are favorites, it may be worth it to keep the ADR. Also, the characters are only at breakfast so you may be able to get a later reservation but it might not be a character meal. 2) Is this your only AK day? If so, can you FP+ any headliners you may want for right after your breakfast or late afternoon? This might allow you to make breakfast, wander around a little bit and then go back and take a looooong nap. (if your kiddos are nappers) or will it completely ruin your plans if Sally Sweetheart turns into Grumpy Gus and needs to call it an early day? 3) How do your kiddos sleep at home? My DD is up at daylight regardless of what time we were able to get home the night before and my DS will sleep past noon even if he goes to bed at 9:00pm. And the same question applies for the adults. If you are a habitual early risers, it may really be a moot point. and finally 4) If you have
MNSSHP, then a full day at AK, how will the NEXT day go? Sometimes the first day after an event "hurts" less than the second day!
For our family, AK is a more leisurely park anyway (as a PP said about going to EPCOT and WS). We want to hit Kilamanjaro Safari, the boys want to ride Everest, get back together for Kali River Rapids and maybe the Lion King show and whatever else may strike our fancy but it's much more laid back, no rushing, for us. But everyone is different and has different favorites.

Having said this, I cannot wait for our next trip (tentatively June 2017) when the new Rivers of Light and so much other new stuff will be available!
Bottom line, you know your family best and what they can tolerate. If you are asking the question, you probably already have a good idea of the answer. Trust your gut and either way should work out fine. And if you miss TH this trip -- Maybe it can be a reason to come back! LOL
*** One other little opinion if you will indulge me: You mentioned 1900 Park Fare. We have been for both breakfast and dinner and much prefer dinner. Breakfast is Mary Poppins, Alice, Pooh, & Mad Hatter and is the typical Disney Breakfast Buffet -- good but nothing spectacular. Dinner however, was FABULOUS! Cinderella and Charming, Lady Tremaine, and Anastasia and Druciella (sp?). The step sisters are a HOOT! And the food is very good as well.