I hope she doesn't do Hair, only because it was already a promo-single, and I don't think releasing that will get anymore people wanting to hear it or buy the album.
I think that she should release Scheisse or Marry The Night. I also feel like if she doesn't release Marry The Night now, it's going to become the BTW'S version of DITD.
I think the best thing about Scheisse is that it's so short of a song in comparison. A radio edit to make it a wee bit shorter (about 15 or so seconds, ala, the German chant). I don't think they should take the entire bit out, but most of at. (Hopefully with a near 4 minute song, she won't make the video 6-10 minutes long like her 4 minute songs, but perhaps more like 4-7 minutes which wouldn't be quite as bad)
That and Scheisse is catchy, has a female empowerment feel to it, and is quite danc-y. (A bit industrial though).
It is also one of the only songs with really catchy hooks and what not.