I was initially in the Flames aren't taking on a forward camp, but now I'm starting to think otherwise. In the off-season, I think all of Frolik, Stone, and Brodie may be gone. Valimaki and Andersson are developing quicker than expected, and the Flames may move a top 4 d-man to make room for their development. Brodie is likely the odd man out there. If the right player was coming back, the Flames could even move Backlund. I know it's an unpopular move, but to make room for Duchene as a #2 centre, it could happen.
Hayes may not be a bad option. He looks a lot like what the Flames had hoped Neal would be. Hayes age fits in a lot better with our core than Neal too.
Dube is definitely off the table for a player like Hayes. I could see the Flames moving Dube if Stone, Duchene, or Panarin were coming back to Calgary, with discussions to re-sign.
Dube was drafted in the 2nd round, and his value to the organization has increased. So he's essentially worth a 1st rounder to the Flames. The price of two 1sts + is too much for Hayes IMO. Hayes is having a great year, but he's not quite part of that upper echelon of trade targets that the Flames will move a top end prospect for.
Basically, my point is that the Flames aren't as constrained by the cap as it might appear. The quality of free agents is so high this year, that moving players like Brodie and Backlund, to make room for legit high end forwards, might be a possibility.