What an exciting adventure! I would definitely take a sleeping pill. In my opinion you will get a more restful sleep. Also, if you have an inflatable/travel pillow bring that as well. I also travel with my own throw to use instead of the airline's blanket. Those things will help you have a better sleep.
As for things to do, do you do any kind of handwork? I knit so I would bring knitting. Nothing too challenging or large. I would probably bring an applique project if I couldn't knit. I also like to use flight time to make my lists.
I would go with the brightly colored locks. I have a red suitcase and it is a not that common type so I used to not have too much trouble. However, recently, I've seen tons of red suitcases in a similar style so I've made some decorative tassels to put on my handle. I have also seen patterns for handmade luggage tags. I was thinking about making some single block tags and that would be fun too.