Hi Adam,
I hope all is well out west.
I will avoid anything related to trying to get a new person to enjoy contra by stepping by themselves around their living room -- I can't imagine how that might be accomplished -- and focus on technical aspects.
1. As you point out there may be issues with sharing video on a Zoom screen and, as you would know, the likelihood of trouble-free video is inversely proportional to the percent of the screen that is displaying video (i.e. the larger the percentage of the screen that is moving, the higher the bandwidth required and Zoom server processing power). Thus, everyone should also ditch the virtual background of the palm trees on the beach blowing around with the waves rolling in. :)
2. I did share a movie on Zoom with family a few months back with some success but the quality definitely improved after I resized the VLC window to about half the screen. The connections just did not support a full-screen video share. Note: Do not share only the video window (which, I believe, will show up on the other ends as full screen), share the entire screen with a small-ish video window displayed on that screen.
3. I am taking uni courses on-line at the moment, using both Zoom and Teams. Last Friday I presented on Teams, window-in-window, a powerpoint presentation covering the entire screen (but having low bandwidth needs) and my smiling face in an inset window (about 25% of the screen) that pops up using (free) OBS software, which actually worked incredibly well. So, you might try putting a youtube video on one side of the screen (that would mean the actual video would cover about 20-25% of the screen and the OBC window (or other s/w that gives you a selfie window) of desired size elsewhere on the screen. Then share the entire screen. Try that out with a friend first and see how that would work.
Last note, it is minimal functionality that is needed in OBS to accomplish this, so the learning curve is about 2 minutes long. Send me a note if I can be of any help. I use a current, mid-range Win 10 laptop.
Bonne Chance!
Ken Panton
Saguenay, QC née Ottawa, ON née YVR (SEA)