Charlotte and Scotty didn't win because they were in GS and rep a tyoical type of behaviour. Not all BB viewers will have seen GS (like me) so can only judge them on this show alone. I don't know how many viewers CBB gets vs GS but I'm guessing that even if Charlotte and Scotty had carried GS fans over to BB that they'd still need non GS fans to like them a plenty too in order to win (esp as they're competing against other celebs, i.e. singers, actors with potentially much larger fan bases).
GS I don't think, by reputation, would be a prerequiste for winning BB, as the BB contestants generally are more diverse than the GS cast (age, background wise) so what BB voters like will spread from end to end, whereas GS seems to cast like for like types for their programme.
I didn't particularly like Charlotte but didn't really dislike her either, and didn't like Scotty at all but certainly didn't hate him, so fans of Charlotte might not even have like Scotty and vice versa. Marnie won't be liked or disliked because of GS or Scotty/Charlotte, and BB viewers won't be influenced to vote for her just because of some association of a show or a viewing loyalty to it.