Tip from an ex- CM...
Orlando's weather is unpredictable. In the winter months it can go from 80 one day, to 40 the next day. I highly suggest bringing jeans, and a light jacket unless it is the summer.
No matter what you do to prevent it, children are going to be tired, and cranky at the end of the day, which makes the parents tired and cranky as well. Try not to let other people's bad attitudes ruin your evening. If you stay until closing, how about finding a nice quiet spot (example between the emporium and crystal palace), and treating your kids to an ice cream, or tell them a story after the fireworks have ended. Let the massive crowds leave, and then make your way out of the parks. You will then (hopefully) insure a seat on the monorail, and insure a seat on the bus back to the resort.
Everyone there is on vacation, everyone there has spent a lot of money to be there, and everyone there wants to have a great time. The thousands of people there want to see the fireworks just like you.
Stop, and smell the roses. Go with the flow. Stop, and sit down for awhile, and just people watch!
Try to get early ADRs for Crystal Palace one morning. Since you will already be in the park for rope drop, go to the front of the castle, and just watch the people running into the park. I promise, it is one of the most magical things I have ever witnessed at MK.
Be humble. There are people at Disney from all walks of life. Some are millionaires, and some have been saving for years, and years, and years just to be able to come for a few days. Two stories I will never forget are... The Big Brothers, and Big Sisters from Toronto Canada, flew down with over a hundred disadvantaged children. They took an early morning flight, went to MK for the day, and then flew back at 11 PM at night. Those children were so sweet, and were so thankful to be there. The sponsers had been doing fundraisers for over a year for the trip. To me, it was just magical to see these kids faces that would otherwise never be able to go to Disney as a child. They were so thankful for just one day at Disney. Another late night I was chatting with this wonder guest. She told me that it was her dream to take her 8 children to Disney. She was from Alabama, they drove through the night to make it to MK for rope drop, stayed the whole day, and drove straight back to Alabama. She started crying, and told me she wished she could do more, but the one day trip cost her family over 1000 dollars, and that is all she could do. Just then her little boy walked up to her, gave her a hug, and said, "mommy, this has been the best day of my life, thank-you". It was so sweet!
This made me cry!