Thing is with the forwards you sign, it's just staying healthy and creating competition from within - I liked what I saw out of Angello and Lafferty and who's to say how good or close Poulin or Legare are as well as the others in the system. I know people WANT a Hall or whatever, but I am ok with the forwards after subtracting Bjugstad.
Because the real issue is shoring up that defense after you dump Johnson and you keep Riikola over him and try to find that solid anchor on the 3rd pair RD. Would another hot shot scoring forward be great? Sure, but mate, we literally have Zucker & Guentzel in the top 6, you have 2 legit top 6 wingers, 1 each for Sid & Geno and right now, you have Rust finding fantastic chemistry with Geno and really it's a rotating group for Sid's RW. Maybe with that extra cap left over, the team does what it used to do, 1yr contracts which doesn't hinder the cap going forward or stifle any prospects this team is spending time and money developing.
But even then, say you did what I said and got rid of those guys...
Guentzel, Crosby, Simon*
Zucker, Malkin, Rust
Rodrigues, McCann, Hornqvist
Aston-Reese, Blueger, Tanev
*Lafferty/Rodrigues - Depending on who that 1yr guy is, you then slot down Simon to that 3rd line.
As for the Chicago thing, mate they're in worse trouble than most teams given how they perform vs their salary cap. They have 7m in cap space next season and have to sign Kubalik as well, the Murray contract they would have to sign and if he's looking at 6m+ they're basically going to have to make do with filling that roster with around 3-4m in cap space (Caggiula, etc are other RFA's).
Also if you do the Chicago route, the team is likely not keeping Rodrigues either (really, no need, I would rather see Lafferty up than him) and try to conserve as much cap space with players from within that are knocking on the door as regulars, which as I mentioned would be the Lafferty's of the system.
Guentzel, Crosby, Saad
Zucker, Malkin, Rust
Simon, McCann, Hornqvist
Aston-Reese, Blueger, Tanev
Lafferty
Dumoulin, Letang
Pettersson, Marino
Riikola, *UFA/Trade*
Jarry
DeSmith
*Maybe a veteran goalie is signed for competition on a cheap 1yr.
Where does that leave us cap wise for a 3D? I haven't crunched the numbers like you.