As of December, I will have stayed 60 nights so will bump from current Silver status to Gold. It's my understanding from reading the threads that my status will stay at Gold only until things reset sometime in February 2017, correct? I then think that 10 of those 60 nights will "rollover" to go towards my 2017 total, correct?
No. The program grants you the status for the remainder of this year, all of next year, and the following year until Feb.
In your case, you will be gold in December 2016 once you hit 50 nights. You will keep gold for all of 2017, and remain gold until Feb 2018 unless you requalify in 2017. (this is so that Marriott has ~2 months to post late 2017 December stays, and fix any missing night credits, etc.)
EQNs are counted through a calendar year (Jan-Dec) and reset on Dec 31st. If you have 60 nights by Dec 31st 2016, you will start 2017 with the 10 rollover nights.
I'm also wondering what happens with any stays I complete during January and February, before the reset for 2017 happens. If I stay 15 nights in Jan/Feb, 2017, will I get bumped to Platinum for "2016", (for maybe only a day!), and then when reset happens, get demoted to Gold? Or, will Jan/Feb nights get counted into 2017, and I'll go from Gold to Silver.
The reset occurs at the end of the year, not in Feb. if you stay 15 nights by Feb 2017, you will have 25 status nights (10 from 2016 rollover + 15) which will reset at the end of 2017. If you want platinum, you should consider getting the Marriott Credit Card that gives you 15 EQN and ensure they post by the end of 2016, staying more, or holding a couple of meetings woth 10 EQN each (see the platinum status for $800 with no stay thread), again all by end of 2016. Then you will have plat until Feb 2018, at least Gold until Feb 2019, and at least Silver until Feb 2020.