OK, a lot of points to answer.
I think we should (since we are giving others a lot of work) we should just ask for one for this stage. If the one you like most has already been chosen choose your second favourite!
On the tone of FIVE CHILDREN & THEM: since this originally started as a re-imagining of Narnia and other magical kingdoms I would start it as pure magic and wonder and gradually reveal the darker side their ‘magical mentor’ figure is keeping from them. And then, hopefully, show that he has a good reason to use these many young lives.
For the King’s Eurphranian I was imagining the Strange and Norrell end rather than Gygax. If they could have fireballed Napoleon’s cuirassiers they wouldn’t have run away. Yes, there would be treaties. I imagine a desk at the F&CO in London that hasn’t seen any action since WWI suddenly becoming relevant again…
WDNE isn’t so much horror (though it has horror elements) as ‘Challengers of the Unknown/Fantastic Four’. Heroes against the strange. The management has its own agenda but the action teams see themselves as heroes and are to some extent justified.
I originally thought of having the characters be all teenage girls with the conviction that they didn’t used to be teenage girls did they…? But I think the thing that would tie them together is that they are all new arrivals and find Happy Valley odd.
I have some writing to do!