Why not just create a simple phone number with twilio that they can text a url to and then it fires a script to download that video and upload it to s3 for them? Shouldn’t take more than an hour IMO.
Mainly because I actually like talking to my friends, and I'm often interested in whatever video/music they want me to download for them.
I have no desire to automate my interactions with my friends, especially for something that's easy enough for me to do and only takes a minute of my time.
You could just look at the logs to see what kind of stuff they download. And since they know it’s automated they will likely download even more stuff. If you see something interesting then maybe you can start a conversation with them at that point.