Could this be her twitter account:
https://twitter.com/ma20040301 ?
They have the same name, and all their tweets relate to the game MONSTER STRIKE (for which Kumatani doesn't seem to be credited, but it's possible she worked on something other than music).
It seems most of their likes relate baseball (from what I've seen) and I don't know if Kumatani has any relation to the sport.
Assuming the kids in their profile picture are her children, they do resemble her when placed against her picture from RocketBaby. Maybe I'm just seeing what I want to see...