This article has been referenced a lot this week, but I don't want to neglect it here, so here's a short excerpt from Bill Willingham on "Fables" vs "Once Upon A Time":
Is "Once" influenced and at least in part inspired by "Fables?"
My best guess, based upon the same scanty evidence is, yes, it probably is, but perhaps not on more than a "this is the type of thing that's in the air these days" level.
Why do you say that? The characters from "Fables" live in modern times, in a secret community called Fabletown, more or less hiding in plain sight, and the characters from "Once" live in modern times, in a secret community called Storybrooke, more or less hiding in plane sight. That seems pretty close to me.
That's hardly damning. Our fantastic literature is rife with "they've been hiding amongst us all along" scenarios. There were plenty of such tales long before "Fables" came along. There will be scads of them long after "Once" has aired its final episode and "Fables" shipped its final issue. If you start with the notion of fairy tale characters still alive in the modern world, the next step of placing them in a secret community seems almost axiomatic.
What about the network? Long before "Once" was aired from ABC, didn't that same network have a deal to produce "Fables" as a TV series?
Yes, but that by itself doesn't prove anything. First of all, I am and always was on the outside of any deals between DC/Warner and any studio regarding a "Fables" adaptation. DC didn't want me as part of the deal making and paid handsomely not to have me directly involved. So it was their baby all along. As such, I was never privy to the details of that supposed deal with ABC. I heard the same rumors you did, that the writers of that project weren't supposed to have made the big announcement when they did. In any case, the ABC "Fables" project went no further than creating an unproduced pilot script. I eventually got to read that pilot, and it was a far cry from anything to do with "Fables."
Willingham is, as always, wonderful. And, yes, the article is Bill interviewing himself. There's lots more and he is quite positive about OUAT, so don't fret if you are a fan. Just go to the full article and read. Yes, the fairy tale playground is big enough for us all to play in!
And while we are here, if you are curious about Fables, the compendium hardcovers are the best place to start. Try the images at the top of this post to explore them.