Is it possible to download full tournament data including every card in each deck and wins losses?
I went and checked all the published data on wizards website and confirmed what you saw with your example and the following is all that is published.

top 8 full lists e.g.:
https://magic.wizards.com/en/events/coverage/ptgrn/top-8-decklists-2018-11-10
archetype percentages, e.g.
https://magic.wizards.com/en/events/coverage/ptgrn/3-0-drafts-day-1-2018-11-09

now this doesn't prevent you from ocring the frame by frame of the live matches to get all played cards [ with something like Googles vision api ] and then making your data set for which cards played in a match most often caused the deck to win. Unfortunately this is the only current way , I could find, to get win data for all decks in the tournament outside of the top 8
In response to your second question there is no established format by wizards for this information as they don't publish a public api for there data.