Re: Is Kakashi dead?
Well, when he first mentioned the blindness to Itachi, we hadn't seen him use any MS abilities. I don't know if he had guessed/researched about it, or if he had already started feeling it himself.
I would guess that the infrequency that he uses special Sharingan techniques past the copy/insight part would make his eye last longer than Sasuke/Itachis, though that is only if it matters what kind of Sharingan use causes blindness.
Of course, Kakashi must have practised his crazy dimension warping jutsu somewhere, so I'm sure he has done it more than just against Deidara and Pain.
If it is any use, he may be in trouble, but that seems unlikely since then almost every Uchiha would have gone blind eventually, and it would be no secret.