Batman V Superman's upcoming debut has often been framed as the make-or-break moment for the DC Extended Universe, but many of the projects set to spin out of it are already in production. Even if the film was to be an outright box-office failure (which it won't be, according to current box office predictions) it's too late to stop production on the already-filming Wonder Woman solo movie and the soon-to-start filming Justice League Part One. Yes, it's always possible for productions to be dramatically retooled mid-production, but the bottom line seems to be that the post-Dawn of Justice DCEU will be making its way to the big screen.
There has been some question as to whether all of the upcoming post-Dawn of Justice DC solo character films - including The Flash (starring Ezra Miller) and Aquaman (starring Jason Momoa) - will take place chronologically in terms of their release, seeing as Wonder Woman is going to take place largely (if not entirely) before the events of Batman V Superman. Now, however, we have a little more information regarding that matter.
Producer Charles Roven, speaking to The Wall Street Journal, clarified that The Flash and Aquaman will eschew the traditional origin story format, saying “While each movie stands alone, they’re all part of one long arc of storytelling.” He went on to praise Justice League and Batman V Superman writer Chris Terrio for digging deep when figuring out the interplay between the iconic DC heroes he's been tasked with introducing. According to TWSJ:
[Chris Terrio] studied red- and blueshifts in electromagnetic physics to think about the Flash, investigated deep sea biology in the Mariana trench to create the world of Aquaman, and read the Greek historian Diodorus of Sicily’s account of the war between Amazon and Atlantis to better understand Wonder Woman [for 'Justice League Part One'].
The Greek History detail is eyebrow-raising, as many modern permutations of DC continuity don't directly correlate the Atlantis Aquaman rules with the Ancient Greek Myth of the same name nor its relationship with Wonder Woman's Amazons. Rather, the DC Comics version of Atlantis tends to feature in convoluted creation-myth stories involving alien influence on prehistoric Earth and among early humans, which could be one reason why the film versions might opt to simplify by drawing a more direct line from Wonder Woman's established Greek mythology influences to the Atlantis of myth. It would be odd for the Aquaman movie to not explore his origins, since his stature as the land-raised half-human son of a scientist and an Atlantean exile typically informs important aspects of his life and supporting cast. On the other hand, it's not unreasonable to assume the film will will touch upon in Aquaman's heritage in some fashion, perhaps via flashbacks a la Man of Steel.
The Flash will likely remain a divisive question-mark among fans for some time, with the popularity of Grant Gustin's TV version of the character making many fans openly hostile to the idea of a different actor playing a different version of the character onscreen. If he's to skip over an origin as well, it opens up the question of what his post-Justice League adventures will be about. Perhaps tackling characters or scenarios that are too expensive for the series to handle, all the better to differentiate the movie version of Flash from his TV counterpart?
The notable takeaway from this news would appear to be that Warner Bros is not especially interested in playing fast and loose with a timeline just yet, and appear to be taking a cue from Marvel and holding at least the first wave of DC films to real-time succession. For example, Wonder Woman is in fact a prequel set during World War I, but it will likely incorporate a modern framing device in a manner similar to Captain America: The First Avenger. If the DC movies will be keeping to a roughly forward-marching timeline, it implies progression toward a bigger goal; that could be good news for fans hoping that the DC Extended Universe culminates with an adaptation of a noteworthy DC Comics storyline like Zero Hour or The Crisis (among other possibilities).
Batman V Superman: Dawn of Justice opens on March 25th, 2016, followed by Suicide Squad on August 5th, 2016; Wonder Woman on June 23rd, 2017; Justice League Part One on November 17th, 2017; The Flash on March 16th, 2018; Aquaman on July 27th, 2018; Shazam on April 5th, 2019; Justice League Part Two on June 14th, 2019; Cyborg on April 3rd, 2020; and Green Lantern Corps. on June 19th, 2020.