Ah, found the Juan Cruz reference. This Chief of Security buys it in the novel Dreams of the Raven
, rather decidedly so: first a species that assimilates people by eating their brains cracks opens his skull with its beak, swallows, and "becomes" him, then a Klingon snaps the neck of this alien hosting his brain...
Nothing definite in the dating of that novel, plotwise. The stardate given is 5302, thus Cruz could still have been alive in "The Enterprise
However, Cruz is addressed as mere "lieutenant" at one point.
And yes, he definitely wears red rather than gold in the novel, even before the blood starts to spray.