Firstly, yes, that does look like Brett Booth is on Nightwing. Respectfully, etc... though of course he is also drawing the covers to Earth 2 and Vibe. but still.
Secondly, expect a lot those?* creative changes we were talking about to be announced at DC today for April.
Thirdly, I have confirmed that, yes, in April, DC are publishing gatefold covers for their New 52 books. And that all these are the first half of said cover.
Fourthly, yes so that means Nightwing is probably fighting The Creeper on the cover of Nightwing #18.
Fifthly, here a few more of those April covers.
Seventhly, I understand that in a number of cases, the relationship between cover and contents was rather Julie Schwartz/Silver Age in that the covers came first and then the creative teams were asked to step up and write the comic to go with that.
Eighthly, what happened to sixthly?
And ninthly, while no publisher is going to call their month "Holy Shit", even if each gatefold is expected to reveal a surprise, as they have been internally, I get the idea that they may call them "Holy Smoke" covers instead.