With the ages of your children and your wish to get them involved, I'd consider a bearded dragon to be honest. They are diurnal so will be awake and ready to come out for some attention when your kids are up, and can be full of personality! They can seem to really enjoy interaction if treated well.
Leopard geckos are also a good choice as they're pretty sturdy and can grow to be rather tame. They are also a good size for small child hands.