After visiting the Secretary of State, I marched into the closest Post Office facility I could find, only to discover they don't do packages. So instead, I practiced my Polish all the way to a familiar post office and requested Express mail again. This time, they could not guarantee delivery until Friday afternoon. I hope it gets there tomorrow, because every day counts. Christmas is going to delay things a bit, so the sooner, the better.
According to our agency, we should get the official referral within two weeks. While we wait, I will start the next wave of paperwork so it's ready to send off to USCIS as soon as possible.
What all this means is that, barring any other paperwork delays, it seems like we'll be flying in February. I've suppressed my excitement for months, but we can see the end. And that's really exciting to us, so we may be annoying to be around :)!