^Right. These are variations in artistic interpretation, like the difference between the way John Byrne draws Superman and the way Bruce Timm draws him. What we're seeing is not a documentary from the future, it's a work of art representing -- and interpreting -- a hypothetical future. No interpretation can be held up as the definitive "true" version because they're all equally imaginary.
As a rule, I imagine the original cast when reading a TOS novel, but lately I tend to prefer imagining Greenwood as Pike because he was simply so much more appealing in the role than Hunter.
And when I re-read Vanguard
a while back, I tried imagining Alice Eve as the young Carol Marcus, but it didn't work very well because I don't know what she sounds like with an American accent.