I suspect that what even Comey wanted was for Hillary to eke out a slim victory so she'd have to govern with more guns pointed at her presidency than John Wick's face in his more recent movie posters.

You should really read his book because that was not my take at all.

Let's not forget the entire reason why the public knew that the FBI had reopened their investigation was because now-retired Jason Chaffetz (R-UT) leaked the letter as soon as Comey had sent it to Congress, a letter he felt he had some professional obligation to send.

Comey's an institutionalist, not a partisan, for better or for worse. His motivations are not as simple as "good for repubs and bad for libs", these people don't operate that way (and thank fucking god because this country would be a total mess if nobody was able to put aside politics to do their jobs).

The DNC's blame in all this is for their actions during the primary. Once the primaries are over, the DNC's role is significantly lessened--the DNC did not make "mistakes" w.r.t. the Comey letter, I'm not really sure how you think they were involved. The DNC and DWS did all their fuckery and screwing up pre-nomination.