I think Tkachuk easily would pair well with Barkov on paper to imitate what he did last season. He's essentially a combo of Lindholm and Gaudreau.
I think he will be great with Bennett as well which would be a high chaos/randomness ozone pressure type line. Both those guys on a line in theory would turn opposition creases into complete chaos break dancing zones. Bennett like Hall IMO thrive on chaos. Tkachuk is a master at chaos, but has never been paired with guys who love playing in that type of chaos.
Like I said though, Tkachuk is a catalyst and not a driver. It's not an issue, you just have to be aware that he cannot jump start a line. If his line mates slump, he slumps one of the hardest on the line. If his line mates are on fire, he seems better than them. However I also say stylistically, there's a lot with huberdeau and Tkachuk. I'm sure the Panthers will figure out how to game plan and build chemistry with him easily.
The Flames also had major issues with foot speed across their roster which amplified a slumping Tkachuk. I don't believe the Panthers have such an issue. Their overall roster is much faster across the board. Their floor on a slumping Tkachuk might be higher than the Flames' floor with Tkachuk. Again, real play will be required to know for sure, but there has been enough glimpses on the Flames to be optimistic he should work exceptionally well on the Panthers roster even if it looks slightly different than what is imagined right now.