I would say do the 1040 (including schedules if necessary) for up to 4 December, and 1040NR for 5-31 December (if you had US source income, otherwise, just the 1040) and the 8854 (2 copies, one with the 1040, the other to the address in the instructions). You can always amend later if something goes wonky.
The lady at the Edinburgh consulate definitely told me that was the date that counted, and that's what it says in the 8854 instructions as well, so I think the embassy were just being jerks!