If I were Lavi, I would be giving Chytil another shot at the top 6 over Zib at this point. Remember, before Chytil got injured last year, he started the season by centering Panarin and Laf, and the three of them looked great together. He carries the puck into the offesive zone well and is the type of guy who can score from the circles with his great shot.
He definitely has top 6 potential. Here's how I'd shake up the forwards:
Panarin-Tro-Laf
Kreider-Chytil-Kakko
Cuyle-Zib-Smith
Edstrom-Carrick-Brod/Rempe
Zibanejad can stay on the PP1 unit but should be replaced by Laf if it starts to struggle. You can't mess with such a productive PP right now.
This also gives Kakko an opportunity to have a bit more ice time to find a scoring touch and a veteran in Kreider to play with. Kreider is a great net-front guy that gives Kakko the opportunity needed to simply get the puck on net with traffic rather than keeping the play to the outside.
This also spreads the veterans/youth players throughout the top 9 so that there is a bit more balance and there is defensive responsibility throughout. Each of the top 3 lines still remains a scoring threat too.
Presently, I don't like how the third line is just a bunch of young guys who need to figure it out together. It's a waste of Chytil's potential. They're contributing to wins by playing low event and defensively responsible hockey, but the team shouldn't be scared to tinker to find the balanced scoring throughout the lineup at even strength that has eluded them for several years now.
At 5v5, Zib produces like a third liner, so he should be treated like one. He has 1 even strength point in 5 games so far. Chytil has 2, but with less opportunity.