You do not say how old you kids are. I flew with my 2 and 5 year old to Europe on an 8 hour flight. They each carried their own little backpack with blanket, stuffed animal and a toys or 2. I carried a backpack and bought a bunch of party-favor type new toys (magnetic Barbie, a few little plastic animals, small coloring book and crayons, travel Magnadoodle, colored pipecleaners for craft, stickers) so I could pull out something new to entertain them occasionally. I also bought a small handheld DVD player (now we have an iPod Touch with tv episodes and a movie loaded). Now they would also probably bring handheld games. A deck of cards (we have the Breyer Horse Card game and Uno) is always good too.
I would lay out an outfit per day on the bed and try to make sure the tops and bottoms mixed and matched. I packed in packing cubes, so when you get to your destination you can put packing cubes in drawers and be done unpacking (one for tops, one for bottoms, one for underwear). Wherever we went in Holland I had my kids wear a home made bracelet with their first name and my cell phone number, in case they got lost and explained to them to show an adult the bracelet if they could not see me. We also had a suitcase that had the 2 normal wheels, but had 4 extra wheels on the bottom (the way the suitcase lays flat) so if they had to walk lots through the airport they could actually ride on the suitcase. A travel double umbrella stroller also came in handy at those ages.
But it sounds like you have the right idea: plan ahead. My dad travelled a lot and always said that if you have your ticket, passport and money you are all set because you can always buy anything else if you were really stuck.
Enjoy the trip!