I don't think 2016 is possible unless PROMETHEUS were to start shooting this Fall, WHICH doesn't seem possible given the shooting schedules of Fassbinder and Rapace... Even if it were able to do so, and Scott is likely to be in high gear while producing both, if you read through what I wrote, you'd see I think AT BEST it would be Xmas 2016 and then 2017 for the second film.
When asked if P2 and A5 will be PRODUCED in tandem, Blomkamp responded by saying he wants to "keep some of his cards close to his chest." So that to me, means there will be some kinda story regarding the making of both films - the two productions - which will involve / overlap each other. Perhaps they will PREP together and then splinter. That sounds like a solid plan from a producing perspective. Since it would create cohesion in the production design/ art dept areas , which Scott is ALL about in his Sci-Fi movies.