I'd have 4K on the right of Maatta (which was a solid pairing in the playoffs). I'm also not as high on selling Murphy as you are.
But, if we were to sell Murphy with no retention (which should not be hard for a big top 4 RHD in his mid twenties making under $4m), we'd be able to sign Strome and Kubalik to around $3m a piece, 4K for 800-1m, and Crow to $3.5m (if he gives in to that). We'd fit under the cap doing that, and that's not even including a potential Smith buyout.
If our backs are against the walls this offseason, trading him would make a lot of sense and would be pretty easy to accomplish.