Sergachev is already signed. He'd be the only one I'd be willing to overpay for. I'd have mild interest in one of the other two, depending on the cost.
I'm completely okay with taking on a bad contract for assets, but it has to be worth it. Johnson for four years at $5M, for a late 1st round pick isn't close to worth it in my opinion...
Carolina got a mid 1st round pick last year for taking on Marleau for one year at $6M, and that was before Covid times... The price should be MUCH higher than that for a similar cap hit, over 4x the term, in this current climate...