Hi, if you have any questions, you can join our discord (linked on the jam page), and we can answer them there as well. But for these questions:
1) No, you can use any game engine, as long as it's playable on an apple device, windows, or WebGL.
2) Yes, 4 per team.
3) Yes, you can use pre-made assets.
4) There is a dedicated judging panel.