My bet is any deal Toei makes will be contingent on the entire series being licensed. Which, of course, includes StarS, which they've been pretty reluctant to touch Stateside. So.
I think you mean SailorStars.
20th anny aint for a couple of years (manga and anime began in 1992). Serena/Usagi's birthday is June 30th. I think it's random cause for celebration.