Believe me, if the interior color wasn't spec'd like a Model T (any color you want, as long as it's black), we would have gotten something else.
When we originally told the San Antonio, TX store that we wanted to get an allocation (ASAP) for the 2019 M2, the first thing the service advisor sent us was an email link to a BMW forum thread on individual (exterior) color that pertained to the M3/M4. I spent quite a while looking at the great colors, reading the stories, and then called BMW NA to ask about the M2. They set me straight, and then I set the SA at the local store straight.
As to red for the interior, it wouldn't be my first choice, but my wife would LOVE it. (I like the saddle/baseball glove shades...)