Holy moly.
First off, we don't move threads to Pending Approval until they're officially submitted.
Second, it doesn't matter given your stated purpose, because you are allowed two project threads. Doesn't matter if they are in ITW or Pending, you get a grand total of two.
Third, we're all quite busy. We try to respond to PMs as we have time but sometimes it takes a little while. I often don't open PMs until I have time to address them, so it still shows at the top of the forum that I have a PM and I don't forget to deal with it. Once I open the PM, the notification disappears and I might forget to go back to it when I have time. If you send me a PM on Monday, there's a chance I might not open it until Friday or Saturday, despite the fact that I'm here pretty much every day. Sending me two messages in a three day period might just annoy me. It probably won't, especially if I know you, but that's always a possibility. Especially if I've had a particularly bad and/or busy day.
Fourth, you can also try user-tagging a member. Type "@" immediately followed by their name. It will send them a notification they've been tagged. But don't abuse it.
Lastly, if you can't get a hold of one staff member, try a polite PM to another staff member. If you had sent me a PM asking about this, I would have already contacted @"DominicCobb" on your behalf by now.