We are from CA. But when we go next month, my SIL and kids are meeting us from the east coast. They have a similar flight as you. My kids are older but hers are 7 and 5, so I have to adjust my regular touring plans.
They land at LAX around 10:30. They will go to the hotel, drop their bags and meet up with us. Since we won't be there from the early morning, we will do things that will acquaint them to the parks- the train, some shows (Aladdin, Crush), maybe the parade.
We will have an early dinner at ESPN Zone. That is what her 7 year old wants to do the most. That should put us at about 7:00. She'll head back with her kids and go to bed. We will get up early the next morning for MM.