Congrats on your wedding, and welcome to UKY.

We're leaving and arrive in NYC on Oct. 21st, will wed on the 27th...is there a better or more conclusive way to schedule my biometrics test to happen soon afterwards (say the 28th or 29th)?
Once you are married, you can apply online for your spouse visa. Once you submit and pay for your application, you are able to schedule your biometrics appointment (remember print out and bring your appointment confirmation - you'll need it to get stamped). The biometrics isn't a test really - you just get your picture taken and fingerprints scanned, and then someone stamps your appointment sheet. (remember to send this to the Consulate with the rest of your application package)
Remember that once you attend your biometrics, you have 14 calender days to get all your documents to the Consulate, so make sure you have them all ready to go. I'm not sure about NYC (and you may want to check), but it may take some time before you can get your marriage certificate - it took me 2 weeks to get a copy of mine. So, if there will be a delay in getting your marriage certificate, you may need to hold off on applying - if you miss the window to get your documents in, you'll need to apply and pay all over again.
Depending on how busy the center is, you may have to wait a while for an appointment; however, you can choose another center if there's an earlier appointment available. For example, when I did it, if I opted to use the center closest to me, I would have been waiting 3+ weeks for the first available appointment. Instead, I opted to drive about 1.5 hours to a center further away, but it had an appointment in only a few business days.
With the closure of the Chicago consulate processing branch, more applications will be coming through NY, correct? Does this mean it will take longer to receive the visa (Spousal) even if you pay for priority?
My opinion - the priority guideline says that settlement priority applications will be processed in 15 business days or less (unless your application isn't straightforward). Unless that guideline changes or you have a complicated application, IMO, I don't see why you wouldn't have a decision within those 15 business days.
We've purchased a roundtrip ticket (that's changeable for a fee) on Nov. 20th - call it wishful thinking:)
For future reference to anyone reading, it's highly recommended
not to book any tickets until you have your visa and have had the opportunity to inspect it for errors.
Also, is it okay to have a faxed copy of my divorce decree - i've been told I'd have to contact the Brooklyn Supreme Court office to get an 'original'
?
You should provide original or certified copies of documents.
You should provide original documents. Failure to submit original documents may mean your visa application is delayed or refused. If you are not able to include original documents you should send certified or notarised copies. (Worldbridge)