Haha, nah, I don't think He-kun's last name is ever mentioned. The "raishuu kara Saito" ("It'll be Saito from the next week") is apparently a Bo-bobo in-story joke. That line in the particular context of that song can also be interpreted as "I'll be known as (Mrs.) Saito starting the next week." I was too lazy to include all those details since they were long and complicated and probably no one would really care...
Anyway, I'm done with the lyrics of Beauty's song, but I need to confirm if it's the theme song to any particular stage before I submit the song along with all that information. I'm guessing it's from stage 4?
---------- Post added at 10:28 PM ---------- Previous post was at 10:17 PM ----------
And look, a request thread in the Lyrics Request section has actually reached Page 2! What an accomplishment! =D