Do you want to resign Guentzel after this year?
If so, how do you get the about 5M you would need to sign him, given he wants something like 8M aav?
If not, Laffy for a single year of Guentzel is poor asset management in my book.
Maybe if Tarasenko is signed for only a year, you could use his cap space to resign Guentzel. But I don't think Tarasenko would want to sign for a sigle season.

I think Guentzel to NYR makes a lot of sense, but only as a rental. Then, will PIT be a seller come deadline?

No from the Pens. That Goodrow contract is all yours.

Guentzel to NYR makes sense as a rental - agree with Blasphem_ Guy on that one. Trade package will be different though. Rangers will def push hard to trade Goodrow during the offseason - solid player but too much money for a 4th line role. Can take that and get 2 players that are younger, play the same style, and will put some similar offensive totals.
Tarasenko is not signing at that salary. Very weak FA class at RW. He may not get 7.5 mil a year again but he won't need to settle for anything under 5 mil.
Rangers aren't signing Brassard - after the serious injury he suffered near end of season he is most likely calling it a career.

Very easy no thanks from the Rangers for 1 year of Guentzel.