Go forward as bad as that sounds to some.
Zack gets put on a short leash with Justice League and both him and WB come to an unspoken understanding that Justice League is the last film he touches as a director. (I think it was going to end up that way before all of this, but more to do with Zack talking about how long he's been directing DC films)
Zack and his wife are still left on the creative team, I imagine the contracts signed would be hard to swallow at this stage, but give Johns the Kevin Feige role while being paired with Charles Roven. Johns gets to focus on the overall universe and comic knowledge while Roven handles the more tradition film producer role. I doubt Johns knows that much about getting a film made.
Announce the Affleck directed Batman film as soon as possible. Ben has all but come out and confirmed the rumors.
Announce a new solo Superman film. It needs to serve as a soft reboot or something. Keep the cast, but change the tone and negative reaction to the character.
Delay Justice League 2. I would assume Justice League 2 (which is slated for 2019) wouldn't go in front of the cameras until 2018. Use 2017 to strengthen upcoming solo films and get the Batman and Superman films in front of the camera. Give Batman the Justice League 2 spot. Find a spot for Man of Steel 2. Release Justice League 2 in 2020.
It would be nice to plug George Miller into Justice League 2 or Man of Steel 2. I'd prefer Man of Steel 2, but it seems WB and Miller might not be on the best terms right now? Honestly, I wouldn't care which one he'd take, but he's old and slotting him into something still 2-3 years away from filming + another 8-12 months in post is a risk.