Welcome, Jen
for your first five chicks, I recommend Easter Eggers. They are friendly, gentle birds.. not too big or too loud.. that lay a green or blue-green egg. Your kids might find that fun.
For your next five chicks, you might find Orpingtons to also be very gentle and friendly.
I'm rather fond of my Welsummers, too, that lay a dark terra cotta egg, so you'll need a few of those around.
Now, your 8 yr old is old enough to join 4H and show birds, but will need a smaller, banty hen for showmanship. Silkies and Old English Game Birds are very popular for 4H.
You DO realize that there is a disease called Chicken Math, don't you? You've already been exposed to it and are sure to come down with symptoms soon, if you haven't already.
I recommend that whatever "design" of coop you choose, that you make it "bigger."