1 - No word count minimum
2 - There are no explicit rules for what can't be included. I am a gore writer who frequently writes about taboo stuff. I'd love to see some entries that really fly the freak flag high.
3 - the answer you got on bsky seems to be correct. Shifting isn't a requirement by any means. Women aren't required to have knots, or they could have them, your choice.It really is all fine as long as you feel like you have elements of Omegaverse in your project.
4 - Yup! that's perfectly fine.
5 - A game jam comes from the musical term of jamming it out, from my knowledge. What this means, is that you are making a project (for this one, it does not need to be a game.) during a specific period of time, and in some cases, totally from scratch. People would have in person game jams that were 24 hours long, or 3 days long, and just make a game during that time. So a Jam, in this sense, is just. making a project in a specific amount of time.