The writer of Nightwing confirmed Midnighter is appearing in the first issue. So he isn't missing. I'd also imagine that Harper is going to be appearing in Detective Comics with the other younger Batman family characters. It would make sense.
As for Earth 2 didn't they confirm in a Q&A that the current Earth 2 series would be continuing? Maybe they are just unsure of what to do with Earth 2 at the moment and haven't decided if they want to scrap everything and start over there or do something else. Guess we will find out in the Summer.