Who are the 1-2 guys you could see surpass Eichel?
Outside of McDavid, no one is really close to his level.
I think both Marner and Ranta are talented enough offensively to win an Art Ross in a "perfect storm" of a career season. With luck - maybe that even happens twice (not that different than Martin St Louis for career arc).
Eichel is obviously talented enough to win awards too (Hart, Ross) - but I think the most likely scenario is he doesn't, with so much top end competition in league (not that different than Tavares for career arc, or even Stamkos minus rockets).
So if Marner or Ranta have such a career year - maybe they win a few major awards and Eichel doesn't. I could even see Aho doing that, probably think Barzal a bit less likely, but others may disagree.
So most likely scenario - Eichel is best and remains clear best among those.
Possibility? One or two of the other guys surpass him.