I don't think Jiminez will be working on AF if it is written by McCann as the text from that panel read that he was working with a big name writer; my guess would be Grant Morrison on something over at DC.
I'd imagine if it is McCann then it'll be in H&M or it'll be in some kind of anthology series (ala Nation X, Age of Heroes) or maybe (less likely) a oneshot.
I sincerely doubt they'll launch an ongoing from no-where.