I would say no on both counts. Neither Cain nor Zub were or are going to kill off Vision.
Vision's been dead already and, as a machine, there's hardly any problem with bringing him back when the need arises - so why kill him again?
While it began under a different regime, I'm sure it wasn't "lost." Rather, I expect it simply was allowed to go through the normal development process and whatever problems they encountered were attempted to be addressed up to the point where Marvel finally had to call it a loss. And its cancellation surely has nothing to do with continuity issues, which would have been easy to fix.
No disrespect to Cain but it's ridiculous to say that Marvel "needed" her.
She'll continue to do fine with her indie work and Marvel will not be the worse for her absence.