I'm generally pretty relaxed about rules, but IF you are planning to submit a game to more than 2 jams I would prefer that all submissions adhere closely to the spirit and letter of Variety Megajam -- you should be striving to make 10 games, each one should be done in a day, and there should be an attempt to follow the prompts.
If someone is planning to submit a game only to Variety Megajam, I don't mind if they take a bit longer or ignore the themes a bit more, but still please only submit games made entirely within December 2021.
I have no plans to personally do a demonstration or stream of any of the games, I don't stream much