I've never seen any activity from them on the weekends, this one included.
The content ID you can get as soon as you start working on the process, the number is visible in the URL from the start. It's the number that starts with 7 zeros.
You can also see it listed in the "For Sale" list click on the title, or if it's not ready yet, in the "Validation" window, click on it's title.
You can apply without the app being ready, so that if they approve it it will be instantly in the contest, but it won't count if they don't approve it in time.
I have one sitting there that was rejected for an external link in it that the back button didn't always return to the game, and they told me Friday. So I fixed it and applied anyway, but I bet the contest is over before they come back to work.
Don't know why they would end the contest on a Sunday at 11:59pm (US pacific time) when they don't work Sundays. (even got a 24 hours left email notice,)