Marry the Night and Scheiße MUST BE SINGLES.
Hair is also a viable single and will probably get released.
So that makes seven total. If Gaga really wants to throw in a curveball, she could release Americano, Government Hooker, or Heavy Metal Lover. I love Bloody Mary but I think its too controversial/religious to realistically be released.
So if I were Gaga's label, I'd say definitely 7, possibly 8. Anymore than 9 is probably not happening, but we can always hope