I actually finally made it on 1/2/17 (local HKG time, I guess 1/1/16 US evening) while on a flight from PEN-HKG as part of a PEN-HKG-SFO J fare. I was Plat before the flight but was EXP after I landed. The last 2016 flights to put me over were on JAL on 12/27 but only reported by AA on 1/1.
The reason I was checking so closely was to try the F lounges in HKG, but they wouldn't budge since their systems still showed me as Sapphire.
1 lounge called AA but gave up after being on hold.
How long does the Emerald status take to show up on partner airlines? A few days?