I went back to the 'Candidates' page on Lostpedia, and found this (on the long list at the bottom of the page of candidates):

51 Austen
Cave/Lighthouse Most likely Kate Austen, who met Jacob as a child when she was caught trying to shoplift a lunchbox. Jacob helped her, paying for the lunchbox, and touched her on the nose. Her name was not seen on the cave, but was later seen in the Lighthouse, not crossed out. It has been confirmed by Carlton Cuse* that Kate's name was on the cave wall, but regrettably did not make the final edit. He also confirmed her name was crossed out on the cave wall.

So, Kate was there, but has been crossed off the list. I would imagine Sayid should be crossed off the list, but, um, I have no control over these things...meanwhile, I wonder whether Ilana, at the time she made the remark to Sun, really trusted Ben's statement that Sayid killed Dogen. Assuming she distrusted Ben at the time, she could potentially have included Sayid in her count. Possibly, had she had the conversation with Sun after forgiving Ben, she would have said there were only 5.

Meanwhile, that same page mentions that Bram referred to Frank as a 'possible candidate'. I don't remember that scene, but I'm sure it did happen.

So that puts the number back at 6. Hurley, Jack, Sun, Jin, Frank, Sawyer. Sun and Jin can both count, I figure, because all 6 are only 'possible candidates' after all.

*I don't know the source for this, though. Just taking lostpedia's word for it.