I think this will develop leading up to the draft. Josh Rosen's stock is at an all time low, and if the Cardinals make it clear they are picking Murray in the week leading up to the draft then that tanks the value even further. In that scenario, he certainly can be had for, let's say a high 3rd rounder and a 7th. That is great value as there is no way a 3rd round QB will have the measurables Rosen will have, it doesn't preclude the Dolphins from using this draft to address the other holes on the team, and it doesn't preclude them from drafting a QB next year. Tank specialists will chime in here and say it helps the tank too. I would absolutely make that trade.
Anything higher than that gets dicey.
Just tossing this out there...looking at the trade value chart, the Dolphins trade could trade this year's 1st, 2nd, and next year's 3rd to Tampa Bay to leapfrog the Giants and grab Haskins or Murray. You keep most of next year's draft AND get your QB of the future in a year when it's quite possible the QB1 will fall out of the top 5 picks. I'd heavily consider it if I were Miami.