I don't know what they're saying, but they're suppoused to make Gackt's trip on elevator nicer.. I don't think he's too pleased about the way she sang his song.. We all know he does sing moving like that but, well, it's not nice.
About Morning Musume.. That's a long long story, but let's just say they don't have a specific numer of members, it can go from 3 to 15. Why? Because this group is made to build other groups or to launch soloist. Out of it have come Tampopo and Mini Moni, for example, but it's good I say that all of them are alike, with very pink and happy sounds, dummy lyrics and idiotic dancing. Specially Mini Moni, whose members are suppouse to measure 1mt or so. That's very short, right?? And they're music is (or at least that's the way it sounds) for children. Listen to Yankenpion (or whatever it's written, sorry, i don't speak japanese) and see.
They're very funny, tho, and will lift up your mood easyly... or will make you punch somebody...