Re: The timing is interesting
Sanders supporters used the same complex malware that has been used by the Russian government, which has instructions and error messages in Cyrillic? Pull the other one. I could believe Israel or China might do something like this and be able to fake things well enough to make it look like the Russian government (though not sure why) but no non-state actor possibly could. From the information we have now, it looks like a question of "which government did this".
As for the timing of the release, that's a bit more clear now. Assange stated he was the one who chose the timing of the release. He does not like Hillary at all, and while a President Trump isn't likely to change his situation WRT to fearing extradition to the US any, I'm sure it gave him some personal satisfaction to screw her.
He's claimed he has more information (presumably from yet another source) that will put her in jail. So I wouldn't be surprised to see another document release in early November, timed to tilt the election Trump's way. Not because he wants Trump to win, but he wants Hillary to lose. It doesn't have to put her in jail, something bad enough to drop democratic turnout a few points is all that would be required to make her lose.
That still leaves the motives of why the Russian government would release these documents to wikileaks. Regardless of whether Putin prefers Trump over Hillary, there are plenty of business interests in Russia who have a history with Trump and would definitely prefer him. One of them probably had sources in the Russian government and managed to get a copy.