Considering this, I think the videos being short may have some risks, I have some suggestions.
Ideally, I think the videos should explain things at least as good as this, with really nice graphics like this or simple ones like this to increase attention, subtitles in different languages (when appropriate), and use analogies for simpler communication.
Some considerations and questions:
Long-form content trumps short form due to clarity, and increased fidelity, so the videos should be somewhat long 3 to 15 mins.
How will this compare to other kinds of educational outreach? Blogs, University tables, local groups?
Addendum #1: according to the 2018 EA survey, most people got introduced to effective altruism through media like books and blogs.
https://image.ibb.co/dQWch0/first-hear-bar.png
#2 Translating material would be easier because of subtitles.
Short videos and the fidelity model.
There are four components of the fidelity model
Breadth: How many ideas can you explore?
Depth: How much nuance can you add to the ideas?
Environment: Will the audience be in an environment that is conducive to updating their opinions?
Feedback: Can you adapt your message over time to improve its fidelity?
While Depth and Breadth won’t be a problem for the venue if the videos are long enough, Environment and Feedback may cause some problems.
I’m uncertain about what percentage of viewers use YT and/or Facebook videos educationally, and about the extent to which they update their beliefs by them.
Concerning Feedback, my intuition is that YT comments are somewhat more hostile than other platforms (i.e. blogs, specific websites). I also think that there is a direct relationship between length and (intellectual/informative) engagement.
Although, you could make video versions of conceptually-like articles. Which are quite short. But I suppose the difference is that it is not aimed at the general population at large, at least not to the extent of regular short videos I’ve seen before.