From Elons twitter comments:
#1 Black matte finish likely to make production
#2 Center locking 20" wheels will be available
#3 Optional tow hitch will be offered
#4 Back seats flip down confirmed
They'll use scheduling to maximize US tax incentive recipients as best they can.
Also Elon mentioned that the AWD option for Model 3 would be less then the Model S cost for the AWD upgrade.