Hello!
1. I have added the link to our Discord to the page but I'll add it here too: https://discord.com/invite/vrvKkP98pY. We thought it was there but we must have accidentally deleted it while changing some text ^^"!
2. The Backerkit campaign will run from May 7th to May 28th (so about a month-ish)
3. Yes we will be updating the demo during the Backerkit campaign (a new version should be out in a week or two that will include most of the missing rules, we try to keep it as close as possible to the final version.)
4. I would say that the game in its current state is pretty close to what it will end up being (minus the visuals and art). There will, of course, be some changes as we continue testing and writing the remaining pages, but the overall game mechanics shouldn't change that much. I might recommend waiting for the upcoming update (around April 10th) since it's pretty soon, you won't have to redo your character sheets if there's some changes!
I hope I have answered your questions, and if you have more, don't hesitate!