As I am a RATHER big fan of Serika Toa, here are a few fun stats to celebrate the extremely long-awaited announcement of her and (surprise!) Haruno Sakura's impending Soragumi takeover!
When Kiki becomes top star on June 12, she will have been a nibante (as wholly official a nibante as nibantes get) for 103 months. For reference, Tamaki Ryou became top star of Tsukigumi 100 months after her debut.
Kiki will be ken-17 at the start of her top stardom. Sou Kazuho was also ken-17, and Hokushou Kairi and Oozora Yuuhi were both ken-18.
Haruno Sakura has one total lead of any kind, shinko or small theater (it was the Never Say Goodbye shinko). The last musumeyaku to become top with only one total lead was Dan Rei (top debut in 1999 with one last minute shinko lead in 1998). Before that, we have to go back to the early 80s. Sugata Haruka (became top in '82), Wakaba Hiromi ('81), Kuroki Hitomi ('81), and Azuma Chiaki ('80) all did it with one lead. Kanna Miho ('85) and Haruka Kurara ('77) did it with none.
Her first named role in the Grand Theater was in High & Low; James Bond will be her second. It's difficult to confirm full cast lists from the 80s, but since the 90s at least, Dan Rei ties her for fewest. We love an underdog!
I have absolutely no way of proving that she is the first musumeyaku to be announced as the next top without first having a proper, performance-themed, on the Grand Theater wall head shot, but if someone is bored enough to dive deep into the internet archives, please let me know!