I still find it very hard to believe that the average movie goer, who doesn't even understand that Batman and Iron Man don't exist in the same universe, is really going to care that much about whether the Flash, Blue Beatle, and Aquaman and the Lost Kingdom are connected to Superman: Legacy.
A lot of us tend to look at the situation from within our little fan bubble, where we are aware of all of the details of this kind of stuff, but the 99% of people outside that bubble aren't going to be aware of that. These are the people who are going to see the trailer for Blue Beatle before some other recent movie, and think "hey that looks good, I think I'll see it". Those are the kind of people who are actually going to be the majority of the audience for these movies, and I can almost guarentee you that they're not going to care about, or even be aware of, what's going on with the DCU reboot.