Therin of Andor wrote:
They could've used someone else. No one would notice.
Like they didn't notice Khan's multiracial colleagues turning young, blond and Aryan? Dark-haired offsider Joaquin for blond Joachim?
Or like no one noticed the switch in Saaviks (ST III) and Cochranes ("First Contact")?
Okay. No one who matters would notice.
It's also important to point out that it's never been specifically stated on screen that Khan's "beloved wife" even was McGivers. That line was cut from the film when they couldn't use Rhue, anyway.
Either way, since were likely talking about what would have been a flashback, people would either, not even know who she is, not be able to tell the difference, or not really care.
The number of people this it would've mattered to is way too insignificant to even worry about.