I'd tell the children.
1. You have a soul and your life is the human part of it, so please take great care of it.
2. If you do what you like as well as you can, plus, you do what you can to learn (at school, with your family and friends), you will have a better chance at feeling useful later.
3. That the world is a wonderfully interesting place, full of music and stories and history and fish and geology and art and sounds and books and and and....parks and oceans and mountains and insects and and peoples, full, full, full of more than we can imagine.
4. Tell them many stories every day, so that they learn to identify with many 'heroes' and with the adventures and experiences of others.
5. To be am active, participating, part of their loving family; share the love, the mistakes, the tidying up, the cooking and cleaning, the kissing, the apologizing...and the cuddling and to always stay close because no matter what happens inside the family, (for better or worse, good days or bad, hard days or harder, great days or disappointing ones) the family is the best place in the world because it is your place. And everyone is human in it!