Diggs, Thielen, Treadwell, and Floyd are locks in my opinion. After that, it is anyone's guess...
The team was reportedly trying to trade Jarius Wright last offseason. Sterling Shepard just went down with a bad ankle injury from early reports... maybe the Giants come knocking with a 6th or 7th round pick in a trade offer for a Vikings veteran slot WR? I would think he makes it, but if any of the young guys impress I could see him being released for a younger (and cheaper) option given his limited role in the offense last season.
As far as the young guys... Fruechte has been impressing in camp and is my dark horse to make the final 53. Good size and speed. Built a lot like Michael Floyd. Adams and Coley will be fighting to make the final 53 and both may not make it. Mobo is a freak athletically, but I'm not sure if he's learned enough to make the team. If he stands out on special teams he might have a chance, but another year on the practice squad seems likely.
If I had to make a guess right now... here is how it will shake out.
WR (6) - Diggs, Thielen, Treadwell, Floyd (suspended 4 games), Wright, and Fruechte
* Coley or Adams makes the final 53 while Floyd is suspended and is placed on the practice squad when he returns