Quoting: DirtyDangles
Non of those guys you listed are 2nd line players no matter who you stick with them.
@Bluetomorrow83
Not my battle, but I thought some facts were in order:
Tanev plays the 3rd hardest minutes of any forward on his team, after Wheeler and Scheifele. He starts a lot more in the d-zone than they do too. He has a positive DFF% and GF% during those minutes. By TOI, linemates and production he's a 3rd liner. He's WPG's best PKer. These things have value to EDM, even if they aren't sexy.
Donskoi plays anywhere from 1st to 3rd line, had the 7th toughest minutes on his team this year and doesn't PK, but man his numbers vs Elites are good - easily best on his team.
Pirri is a 4th liner, gets fantastic results (71 GF%!) but in a fairly sheltered role.
Nylander is a good 2nd liner, has the advantage of being younger than the others, but played very sheltered minutes this year due to starting late. Even last year though, he played the 7th toughest minutes on the team, hardly a 1st line driver.
I thought I would add each player's 5v5 p/60 (and TOI) - and their most common linemates - for the last few years for context.
Nylander
16-17: 1.77 (1050:46) - Matthews, Hyman
17-18: 2.38 (1134:55) - Hyman, Matthews
18-19: 1.78 (708:49) - Kadri, Matthews
Donskoi
16-17: 0.98 (736:52) - Couture, Ward
17-18: 1.85 (842:40) - Pavelski, Meier
18-19: 1.90 (1008:55) - Kane, Hertl
Tanev
16-17: 0.53 (452:55) - Lowry, Thorburn
17-18: 1.41 (640:19) - Copp, Lowry
18-19: 1.53 (940:19) - Lowry, Perrault
Pirri
16-17: 0.95 (571:01) - Lindberg, Fast
17-18: 6.02 (29:54) - Tuch, Karlsson
18-19: 1.91 (376:40) - Tuch, Eakin