Correct. Wonder Woman 1984 takes place after the events of Wonder Woman, but before the original Zack Snyder timeline.

Blue Monday was actually released as a 12-inch single in the UK on 7 March 1983 through Factory Records. It did not appear on ANY US recordings until 1986 when the album Power, Corruption & Lies was re-released on CD format for the first time. However, this does not mean the song did not exist until 1986 and could still have been known to American fans of the song via import.

Blue Monday - Sebastian Bohm Frankie Goes To Hollywood - Welcome To The Pleasuredome

Shown in the Wonder Woman 1984 trailer, Wonder Woman is seen throwing her tiara toward a camera, most likely trying to keep her existence secret.

Add:

Wonder Woman tells some of the eye witnesses to "ssshhhh" and that helps keep her secret. She also destroys security cameras after landing in front of them and of course, that helps keep her secret.

They should have kept Zack Snyder and Allan Heinberg. It was internal politics that created this discontinuity. Hopefully, we can pretend this movie was never made or is never referenced into the next storyline.

Beyond general theming, there is no significance to the year 1984. The original television series (Wonder Woman - which aired in 1975 and starred Lynda Carter) ran for three seasons and covered two distinct timeframes. The first season took place during WWII, while the 2nd and 3rd season took place in the more contemporary late 1970s. With the highly successful 2017 reboot (Wonder Woman), and in an attempt to mimic the original tv series, writers Patty Jenkins and Geoff Johns set this installment of the DC franchise in 1984, long after the end of WWI, the era of the 2017 movie.

The 1980's are regarded by many as being a decade of greed and selfishness in America. Since selfishness is a main theme of the film, that's probably why they chose to set it in the 1980's.

Possibly, the particular year 1984 was probably chosen because that year evokes some cultural recognition. That is due to the acclaimed George Orwell dystopian novel "Nineteen Eighty Four", which was first published in 1948. Beyond that, however, this movie seems to have little if any specific connection to the novel.

It's Etta Candy, Steve Trevor's secretary from the first Wonder Woman movie.

Yes, of course.