It has to be bait to trace leaks.
Otherwise, it makes zero sense. Mike Aiello's well aware of what people thought of the crowd FNAF brought. I can't see any scenario, during an anniversary year no less, that he signs off on Fortnite as an amazing idea.
Not to mention, what does a Fortnite scare zone bring? Nothing. It's like Dead by Daylight. It's largely known for their licensing deals. If Universal wanted a scare zone that was a mishmash of horror IPs, they could create their own. They'd have to go clear rights for all the properties anyways......
And more to the point for spec purposes, when has Universal EVER announced a scare zone before announcing at least one house? They haven't. Do we really think they're kicking off the hype train with "Hey, we're going to theme part of a street after Fortnite"?