The "best qualified candidate" is not generally an objective measure -- if you
can be more productive with someone your own gender and race, then that's all
to the good, the largely American taboo of racial and gender sorting notwithstanding.
Doesn't that depend on what stage you're in and how you are bringing them in? Like I'd you already have a company set up and you are going to hire them as an employee without sufficient interest, then it does apply. If you're not giving them sufficient interest in the company (10%?), or it hasn't been formed yet, then I think it doesn't.
There are also minimum employee sizes before racial discrimination law kicks in, I think 15, or 5 if you’re in California, but that is from rapid googling.