THEORY: Shazam and Green Lantern Corps

Theory: 

Either DC is trying to get a head start with upcoming movies to give directors enough time to write scripts and casting OR they are moving movies around and up in the schedule

Based on their previous slate Shazam's release date was April of 2019 and having a meeting with DC 2 years in advance doesn't seem to out of the ordinary. The meeting was most likely about the script and maybe some preliminary casting. Now if I did not know any better I would say that the movie is being fast tracked but I do know better. Given other Warner brothers release dates for Aquaman, Fantastic Beast 2, and not wanting to compete with marvel movies I think the movie is staying at its April 2019 Release date 

On the other hand the Green Lantern corps movie which was slated for July 24th, 2020 is three and a half years away. They announced who would be writing the script. In my opinion I think that this movie is being moved to 2019 and I think we will see Green lantern before we see Justice League 2.