A couple of thoughts. In support of "the towel" as a blockade: getting wet and retaining moisture could be very helpful in keeping humidity up (important when there's air conditioning during the summer and heat during the winter). Towels can be bought for fairly cheap and easily washed, so just have a stack and change daily.
While the cricket gas isn't harmful to humans, many people and I suspect most children are allergic to cricket poop. Insect poop is considered one of the leading causes of respiratory problems in children. So, if you do decide to try keeping large numbers, make sure the container is away from the kids.
As you are planning to gutload the night before using the crickets, you can use any number of commercial cricket food products for your "daily feed". I would suggest you give them at least 24 hours with "the good stuff" before using them though. I've found that "full crickets" don't throw themselves on the kale and dandelion leaves the way I'd like them too.
)
