Yes, this event occurs on the last weekend of the month @01:00am UTC
No, you can work on any tech project like open source library, any learning activity, startup idea, proof of concept etc. The only requirement is that you must release something in public within 48hrs.
Yes, ofcourse, If you have any technical question we can arrange a call/chat and help you.
No. As long as it is kinda usable and communicates the message of the product to the user its fine.