Whoever wrote the anonymous letter seems to have copied the wording of US Ambassador to Russia Jon Huntsman or actually is Jon Huntsman. But the NYT also could have just used Huntsman’s words to divert attention from themselves, which I think is a plausible answer.
Yes....thing is, the letter also pointed to Pence. Misdirection seems to be one of the goals. I loath Huntsman...so it would not shock me if he was involved.
Whoever was behind it did not work alone. They dropped it right after the Woodward book.