Sounds like your travels went smoothly. My husband does the same with the carseat - he boards first and installs it and my daughter and I are the last on board. He doesn't have to deboard as we only have one little one. I assume that is why you deboarded - to help you wife with your twins.
Those stickers are great - we have them packed in our travel bag and ready to go! One other great thing we use are the crayola special markers - can't remember the name, but they only mark on the special paper sold with them. So, kids can scribble away, but no mess. We only use these for flying with our daughter, but she loves them.
Cheers,
Vanessa