No clue on the Etherians (there's many more species than just the movie-focus grays or lizard people afaik.)
As for 1 and 2, Bill Cooper's research seems to suggest that yes, but the deal wasn't the only one available (coulda been a spiritually focused knowledge expedition through pleadians (supposedly), but that came with a preclusion for disarming all the nukes). Just getting out of the devastating WWII with a focus on the nukes this was off the table.. so moar tech for some mutilations instead.
Being haunted? likely.
Some sauce materials:
https://bibliotecapleyades.net/sociopolitica/esp_sociopol_mj12_1.htm
The full read on the link is rather informative.