It's lovely that you're taking the dog on, and I hope it all works well.
Now, forgive me for giving advice not asked for, but I feel I have to ask these questions, which might actually help you with your plans. Obviously you may not wish to answer on here, but perhaps just consider them.
Do the parents of the children know their childminder will have a dog on the premises, and if so are they happy with that? (One does not exclude the other, but it might be worth checking re allergies, fears etc.)
Has the dog any past history of aggressive behaviour?
Does it bark excessively?
Has it happily used a crate before?
Hth