You will want to bring the things that you know you will need in your carry on. Bring all necessary medications. Bring one or two changes of clothes. And all of your important papers will go is into your carry on as well. It is just really wise to do things this way. It is better to be safe than sorry.
There will always be a line for those with special needs at the airport. Please take it. Ask someone if you do not see the line. Bring your liquid medication in their prescription bottles.. I don’t think they are allowed to x-ray those.
You will want to bring some lightweight blankets for you and your little ones. The blankets they give out are unlikely to keep anyone warm.