Who should be my top target at the 7th pick in a 12 man ppr league

If you're talking redraft, it's really a matter of who falls. Most likely there's two left of Amon Ra, Chase, Hall, Bijan, and JJ, so you're probably deciding who your favorite of those remaining are. Personally I'd avoid JJ over the rest of them this year because of the Viking's QB situation, and there's a decent chance JJ drops to that pick, so I'd go whoever else is available of those 4.

Dynasty - one of the WRs in that range

Or Bowers if he falls which I doubt