If Ghostbusters is announced on June 8th, it's only because that's what I asked Santa for on my birthday this year.
But FWIW, I'd think Ghostbusters seems like a more "safe / expected" announcement- out of all the still-rumored IPs, I think it makes sense to announce A Quiet Place first. Just look at this thread, most of the Ghostbusters spec seems limited to "which movie" vs. all the discussion for how AQP would work as a haunt, would they use puppets, etc.
Just IMO, announce whatever can sustain hype + discussion throughout the summer as the first IP, so people are talking and guessing up until opening night (or, Unmasking tours haha). Ghostbusters is awesome, but I'd bet it hardly draws in any newcomers and the hype after the announcement dies down pretty quickly.