if you want to eat at your hotel and make it for the first and much quieter hour of EMH, from 8am to 9am, then you need to be at breakfast for 7.30am.
you can ask for breakfast in the park though. it might not be on every day while you are there, but certainly ask for it at your hotel when you check in. If you get breakfast in the park, choose 9.15am or thereabouts. That way you can still have your earliest hour of EMH, then breakfast without having to leave the park, then you're ready for ropedrop or the studios for before 10am
with the ages of your children, anywhere really will be okay for them to see Dreams, without getting blocked too much by other people.