Interesting stats. Re: crossover from other sports, I would think the aerobic fitness and explosive training of basketball players (especially guards) would make them likely to break 12.
Anecdotal: I ran 11.8 in some BS campus "meet"a couple of years into college (obviously a couple of years beyond age range being discussed) without any specific training or proper footwear. I was playing a lot of ball at the time. I always had good footspeed over short distances, but my explosive strength and conditioning were peaking from the short sprints, lateral shuffles, and jumping. I'd play for hours on the weekends. I'm only about 5'9" (and white) but could dunk a regulation ball off the floor/drive (although not always cleanly), off a miss with proper timing, and a tennis ball easily -- half-step off both feet. I took the whole thing as a diversion and didn't push the last 20-30 meters so 11.8 sounded slow to me. I can think of several guys I knew who could have walked off the basketball court and likely run sub-12 on a day of rest.
Anyway, I'm a good bit older now and a hobbyjogger over distance compared to the elites here, but I still go back to basketball when I want to jolt my training.