We like her a lot too! All the date options are characters from our previous games. Yanmei herself is from Eons Lost: Arrival. If you wanted more Yanmei that's where you can go!
You found a very old comment! The game in question was mobile-only, but due to not maintaining the iOS and Android versions (as well as the cost) it isn't available in the app stores anymore, and thus is (unfortunately) unavailable for play. This does make me quite sad personally as I still would love to explore the Eons Lost universe more, but perhaps it will come back in a new form one day.
In any case, I'm impressed somebody scrolled so far down to find this particular comment. It's weirdly heartwarming.