Okay so, I got a response from Marty Basto at TopWebcomics via my support email and they said that yes, that email was from them and was able to answer the few questions I had for them about it and let me know that it's still early days but that they hope to launch around sometime in June.
Part of the reply: "The project is moving along. We’re adding new features every week or two. We’re hoping to launch around June.
Right now, we’re busy uploading series to fables so creators can hit the road running.
What we’ve done with Fables is set up an advisory council on Discord with members who were willing to share their thoughts with us."
I went ahead and joined the Discord server via the link in the first email since they'd confirmed it was legitimate, and I'll be exploring the server a bit more later.
As a reminder, from my partner who works in the tech world: You can't be too careful with emails you get, it never hurts to be really cautious.