I've read both those accounts. The Dutch intelligence bit is unrelated to the DNC; they claim the same outfit they were surveilling is involved. They did not observe the Russians hacking the DNC. Read the story carefully to see the timing.

As for Guccifer, the evidence indicates he operates out of CST (based on tweets and uploaded file timestamps), hardly where a Russian hacker would be situated.

These are both pretty weak as evidence, not what i'd call substantial.

And yet Wikileaks denial of them getting the emails from Russia without any proof whatsoever is somehow not weak? How would Wikileaks even verify that they were not dealing with a stooge of Russian intelligence?

Easy: they would have direct correspondence with the leaker and could easily validate it's a DNC insider. To be clear, I don't consider this to be strong evidence, I just consider it to be counterevidence that should cause us to be suspicious of the main narrative.

Meanwhile, of the above two articles, one (the Dutch intelligence bit) has nothing to do with the DNC. This leaves only a rather shady character, Guccifer 2.0, whose actions are pretty unprecedented in history: a hacker who announces what they did, seeks interviews, and crows on social media.

Why, exactly, would Russian intelligence set up such a persona? If their intent is to aid Wikileaks, why would they undermine the Wikileaks narrative that it was a leak, not a hack? Guccifer makes no kind of sense unless we believe that his entire purpose is to point the finger back at the Russians, as he quickly succeeded in doing.