Careful. You will be called a "troll" if you dare question how this film could possibly have cost $300MM, and/or how that is reflected in the end product vis a vis the box office. Never mind the fact that the same conversation is had in virtually every other thread once a movie comes out, and the fact that Bosco, who normally reliably posts his very useful box office charts on Sunday evenings, has one conspicuously absent for this movie. Perhaps the optics of posting this film with a negative first week multiplier was not anything he felt would warrant an honest conversation. Better to name call someone a "troll" instead. Easier too. Of course name calling in debate is usually the first resort of a person who already knows they have no leg to stand on.
To your points, however, yes I have also read that whatever plans for any additional JLA movies anytime soon have been scrapped. Flashpoint has been quietly put on the shelf as well, at least for now, primarily since the intended plot of that film involved meeting alternate members of the JLA. Green Lantern Corps will be at least pushed back until they see how Aquaman performs first. Affleck is out, Cavill and Amy Adams most likely are out as well. Suicide Squad 2 will probably still get made. Shazaam is fairly deep in pre production, but it is not a lock to move any further at this point. The Batgirl movie is very iffy now and so is that Joker movie. It all basically comes down to how Aquaman does. I would prefer it not having to come down to that particular movie since putting that character in a solo film was already risky proposition in the first place. But we'll see. As you said, WB will be focusing basically on Batman and Wonder Woman films until the wheels come off, and these will be stand alone affairs. WB is basically going to abandon the interconnected Marvel formula. And that might just be the route they should go at this point.
-J.