I think there are two paths you have to look at. One where Draisaitl plays RW, and one where he plays C.
I'd suggest we play him at centre all year. In that case we need to look at signing a scoring RW. Someone who can rifle the puck. You need to look at Vrbata (55 points last year), Vanek (48 points last year), and Williams (48 points last year).
Marleau plays C/LW but did put up the most goals of any UFA with 26 last season. Could he slot into a RW role?
I'd be happy with any of these players playing RW for us. RNH has shown he really lacks the offensive instincts to be playing on a real scoring threat line. I don't think we can afford two, can we? Perhaps with the Pouliot buyouts it's possible. Maybe just one, and Beauchemin? Or Markov if we can afford it? I know it says we have a LOT of cap space right now but other people are saying due to bonuses and other issues, we have a lot less. I don't know the truth myself.
I would go with Vanek honestly. He won't be expensive, and signing him would allow you to probably sign Marleau as well. Williams seems to be a hot commodity and rightfully so, but I think Vanek would excel playing with McDavid/Draisaitl rather than his linemates in Detroit/Florida.
Marleau-McDavid-Slepyshev
Lucic-Draisaitl-Vanek
Maroon-RNH-Strome
Caggiula-Letestu-Kassian
Your 1st line is all speedsters. Marleau and Slepyshev can keep up with Davo and both can wire the puck.
The second line is slower and more methodical. Draisaitl and Lucic worked well together, and adding a pure sniper onto that line would be dangerous.
Honestly I think we need a puck moving defenceman more than any forward, although that might be an impossibility at this point.