Short answers, pulled from the story.
Warner Bros. Pictures began developing a live-action Justice League film in February 2007 with husband-and-wife duo Michele and Kieran Mulroney hired to write the script.
Zack Snyder stepped down from directorial duties in May 2017 following the suicide of his daughter Autumn, after which Joss Whedon assumed control to oversee post-production and complete the film.
The studio announced two months of reshoots in London and Los Angeles costing approximately $25 million that brought the total budget up to an estimated $300 million making it one of the most expensive films ever made.
Principal photography began on the 11th of April 2016 at Warner Bros. Studios Leavesden and various locations around London and Scotland with additional filming taking place in Chicago Illinois and Djúpavík in Iceland's Westfjords.
Snyder officially confirmed in May 2020 that his cut would be released for HBO Max service in 2021 after posting photos showing boxes labeled Z.S. J.L Director's cut on his Vero account asking if they were real.