We don't know what Murray and Samsonov will be. I hope they're the best option in hindsight. I hope at the end of the season (to whatever team end, win or lose) that we have the fortunate problem of having to choose which one to move forward with.
As for Lankinen being the equivalent of Mrazek...Well, Lankinen is: Cheaper; Healthier; Younger. All things being equal, Lankinen, purely on those qualifications is the better choice to me. However, I think Lankinen's underrated and wasn't able to display his finished form.
I say on a decent club (ie Nashville, Toronto, etc...) Lankinen sees his way to good backup numbers. I think he translates to a consistent .910 - .915 save percentage and a somewhere between 2.60-2.90 GAA.
That's my faith prediction. And I think Charlie Lindgren surprises this season in Washington.
At any rate, we'll see.