There's a good and bad side to the news that Cathy Yan would be directing the Harley Quinn spinoff, Birds of Prey. The good is that Yan is a talented female director getting her shot at a major franchise with a huge star in Margot Robbie. The bad is that it comes at the expense of Suicide Squad 2, which has apparently been delayed from its planned shoot at the end of the year. Variety's Justin Kroll tweets the details...
BREAKING: Cathy Yan tapped to direct BIRDS OF PREY, the next Harley Quinn pic which will shoot at the end of the year. WB pic this as the next pic after Christina Hodson blew execs away with her script— Justin Kroll (@krolljvar) April 17, 2018
Kroll's point is a good one, but a more relevant example would be the way Wonder Woman was introduced first in Batman v Superman before launching into a solo movie. That worked like gangbusters, and Warner Bros. hopes that plan works again for Aquaman.As for SUICIDE SQUAD 2, clearly moving out of 2018 shoot. The move to go with BOP not only had a lot to do with Hodson's script but also the idea of doing with BATGIRL what Marvel did with Black Panther in CIVIL WAR by introducing them into universe before giving them own film— Justin Kroll (@krolljvar) April 17, 2018
And I guess this serves as "confirmation" Batgirl will be in Birds of Prey, which makes sense considering Christina Hodson is also writing her solo movie.
As for Suicide Squad 2, the last we heard it is to be directed by The Accountant's Gavin O'Connor. Considering how popular that film was despite poor reviews I expect a new start date will be revealed soon and they won't keep fans waiting too long.