That's what I think too.
Hillary was sinking in the polls after Trump did well in the debates. The emails were becoming a big issue again. So Hillary needed Comey to exonerate her right before the election.
Good thinking. I think it had to do with putting the Huma/Weiner laptop rumors down too, more than just the e-mails alone. That was the reason he gave, since there were rumors out there raging at the time about Hillary and child porn together on that laptop, that they were trying to disprove.