One of the fake credits in Episod 1 was for a Babs Digby. The 40's sitcom "The Life of Riley" featured characters Babs and Digby and popularized the phrase "What a revoltin' development this is"
which is also a catchphrase of The Thing . To these Easter Eggs hunters that was the first sign of FF being in Wandavision, so that's why I think they would have picked up on missing astronauts...cause these fans are insane lol.