No one ever said it was Humans.Vulcan being 'conquered' by humans
Sarek's "race" was conquered, Vulcan never has been conquered. Those two facts can easily both be true. T'Pol is white, Tuvok is black, Vulcan possesses different races.
(and yes, some people don't like using the term race)
YMMV, in Trek when possible I side with the established precedent first.The prevailing wisdom has always been that later information overwrites earlier information
It is Trek canon, and firmly exists.Do we really need to bring up "Turnabout Intruder"?
More likely she did it to obtain wealth untold.Vash did it for the same reason people do MMA or alligator wrangling or space diving = the thrills.