About your first question (who is the director), and Michael Bay rumors, Millar said:
"Hi Russ, but you must be getting mixed up, bro. Stylistically, he'd be amazing and he's good at spectacle (which is what was missing from the last one). I'm actually a huge fan of Bay. Not into Bad Boys 2 or Pearl Harbour, but The Rock is one of my fave action movies EVAH!
PS It's not Bay. The director will be named soon because if we don't have Superman by January we're jumping onto something else together and then he can be unmasked."
About your third questions... forget it! He will never reveal anything more detailed like a review or anything (even it is a spoiler free) simply because i dont think he would like to tell his story to everyone.
Ultimately, he is going to give more details, but only after Warner says YES or NO to his project, and he be able to move forward to other projects. Mabe even adapt his story to comics. How knows?