Some thoughts from a Make and Take veteran:
Hobby Boss 'Easy Builder' kits. Our IPMS chapter received a donation of these kits. In the current calendar year, as part of our Make and Take program, we have helped over 400 kids 5 to 18 along with their parents build one of these. The box says 14+, but we've worked with the younger ones and pointed out small part hazards as necessary.
Be sure that you get the parents involved. You are not a baby-sitting service.
They are mostly snap together but we have found some fidley-bits that need some glue. They are pretty reasonable, about 10 bucks at Hobby Lobby. Less when you factor the coupon.
We don't use knives. Get a pair of flush cutters, those from Harbor Freight tools will do. Your good pair may grow legs. Sanding sticks from Sally Beauty Supply, Moms know about these. We do use Testors Red tube glue, under supervision. Squeeze a dab onto a yogurt cup top and use a toothpick to apply. CA or Tamiya liquid is a leader-only tool,
Build one before everyone gathers. You have a finished example and you are not stuck looking for parts and loosing everybody's attention.
Everyone gets the same kit. You don't need to try to explain why Billy gets this kit but Suzi gets a different one. It is easier on you too, once you learn the kits idiosyncracies. If someone shows interest provide them with a different kit, perhaps one which is a bit more complex.
The Hobby Boss P-47D is actually pretty well done. It would need to be painted (we don't have time to do that). There is something else you could do with them. The same thing with decals - work with Mom & Dad later. There is also make a line of pre-painted snap together aircraft which are about twice the cost.