I think # 3 refers to Sarah Michelle Gellar and Freddie Prinze Junior.
'Buffy the Vampire Slayer' is certainly a catchy name and, although the show was a big hit, SMG was only ever a 'B-list' tv name. Her career has also definately stalled of late.
Additionally, a Laineygossip blind item from a while back seemed to say that Freddie remains foolishly loyal to Sarah, despite her tumultous mental state.