The whole thing is a joke. The Sub Pop cofounder also said in his "confirmation" comment that several other dead people would be playing alongside Love and Nirvana, but the dead people were sufficiently obscure that no one got the joke. Only after a follow up statement from Sub Pop asserted that Jimi Hendrix would join Nirvana on stage did everyone get that he was mocking the original rumor.
Lesson: Comments are evil and all comments sections should be closed forever, as the Times is learning. It's either that or read comments carefully, take them with a grain of salt and keep some perspective about them, especially when Courtney Love is involved.