So its purely a coincidence that they are both having a career year?
Not IMO. I think its possible to say that it would not be impossible to replace Strome's support for Panarin while Panarin probably is the only one in the universe that can help Strome as much as he does. But that doesn't mean that its not a two-way street. Strome is a really good fit next to Panarin. Strome isn't good at skating the puck up ice and Panarin is extremely good there. But Strome is good around the net, fairly strong on the puck, has a solid RHS, and so forth.
I think that Ryan Strome has the same issues -- not worse though -- as Kyle Turris and Derek Stepan have, and a few others in their mold. They aren't strong at all individually, skating the puck up ice, dominating other players physically, stickhandling, they don't have the extremely good vision etc. As a result, their production can fluctuate a lot, and its possible that they can look like really valuable players when things are going their way, and be very frustrating to watch when things aren't.