I ask because I've been trying to rank the hierarchy of H!P next leader. Rikako is either 5th in line or 8th in line. 3rd gen S/mileage started performing in late 2014. 12th gen MM started performing in 2015 as MM15.
It could probably end up similar to Ayacho/Mizuki's duo leadership: With Miki + Rikako, Maria + Rikako, Akane + Rikako, etc.