And well, Simone is a pro and at a different point in her life than tokyo, I can't imagine she needs both coaches there all the time. Cecile (if laurant is the chosen coach) can likely find her own way to the Olympics and probably has family/friends who will put her up so she can watch both diving and gymnastics. Hell, she could make a deal with NBC to provide a few interviews/analysis bits like they used to do with Bela after he retired. Either way, I wouldn't worry about who/what coaches are allowed.
Same thing with Alicia vs. Chellsie. If there is any value to the USOC or NBC in having both there, both will be there. Simone and the gymnastics team are likely going to be their marquee sportswomen--the (basically) guaranteed medals. Other than Katie Ledecky and the basketball team, there aren't tons of "big name" veterans for NBC to hype. If they need the cast assembled around Simone to fill their airtime, they'll find a way to do it.
Also, is it required that the athletes stay in the village? Simone is a married woman and while she might want to have the "olympic experience" again, she's also wealthy, a few years older than most of the probable team, and might prefer to sleep on something other than those sex-free beds.