So will draining. I've done the extraction and then lifted the car and opened the drain plug too, there's maybe 0.3L of oil that came out afterward. I did this on both of my MK7s and the results were very similar. When you're talking about ~6L of oil in your motor, .3L is not really very much. Similar videos on YouTube showing the same thing.
What a good idea. Doing this before my next change. I typically push in until I hit bottom, then push another 2" or so to make sure the tube is laying on the bottom of the pan on its side.
Some dealers do, but I have seen Audi service documentation, perhaps even posted on this forum, advising technicians not to use extractors.
The two dealers closest to me explicitly do not use extraction and when asked why the service advisors at both dealers said that that was not VW procedure. This was ~2 years ago that I asked when in for warranty repair and was wondering about extraction, so maybe this has changed.
All of that being said, I like using my extractor and will continue to do so every 5k.