Updated after including the last game:
Bryan Rust: 9 points in 25 playoff games after the 2017 cup win
Jason Zucker: 11 points in 40 career playoff games
Kasperi Kapanen: 9 points in 30 career playoff games
Jared McCann: 3 points in 11 career playoff games
Zach Aston-Reese: 4 points in 22 career playoff games
Teddy Blueger: 1 point in 10 career playoff games
IMO this team has about 7 players who are actually built the way you want them built for playoff success: Crosby, Malkin, Carter, Tanev, Letang, Dumoulin and Ceci. I'd also include Guentzel (who's hurt right now if I had to guess) and Matheson (who's been fantastic in this series) in that group as well based on actual playoff results. Outside of that group, the Penguins are just littered with soft straight line speedsters without any offensive creativity, soft defensive depth players without any offensive creativity and soft and undersized puck moving D.
This roster is just so monotone. You have literally multiple of the same exact player throughout the lineup. Where's the net front presence? Where's the offensive creativity on the wings? Where's the pure goal scoring talent (not just putting up goals, I mean actually shooting talent) on the wings? Where's the physicality on defense?