From a spoiler a while back from another site who had a friend name
Kelly, who was just entering the house. Kelly supposedly moved in to replace Lisa after she graduates.
She said Jill was the last of the originals still in the house.
She said these were the people in the house with her:
Jill, Kim, Christie, Jodi, and Lisa (a different Lisa)
sounds like Lisa and Jill are the last to go.
(according to spoilers from Betteboop site)