I feel this forum overrates Chytil and underrates Lias. I think both will be fairly solid. In Lias' case, we've never seen him playing with talented wingers since he was drafted.
I think it's imperative the Rangers start the season with Kreider and Buchnevich on the roster. Attaching Lias to Howden on the 4th line will do nothing for the development of each.
Think something like:
Panarin - Zibanejad - Kakko (Don't overthink a potentially very good line)
Kreider - Lias/Chytil/Howden - Buchnevich (Each are given chances to earn the 2C spot, with Strome)
Lias/Chytil - Strome - Kravtsov (Strome acts as steady presence on the 3rd line; Kravtsov starts there with less pressure and can be mixed/matched)
Lemieux - Howden/Lias - Fast (Self explanatory) + Nieves as the extra forward
Namestnikov should go in any scenario. If extra cap space is needed, attach assets to unload Smith, consider a buy out, etc. That forward group can make the playoffs, and can take a nice leap forward this season. If they underwhelm, trade Kreider at the Deadline and re-evaluate next offseason.