So we are taking USA Transfers from the airport. They will stop at a store on the way to Temptations? Since we are taking a red eye, I would prefer to just get to Temptations. For time spent as you say Steve, and stop time, I'd think the minimal additional cost might make a trip across the street easier.
Buy at your duty free before you leave the US. Then you just carry it (up to 3L per person). In my experience, that's your best bet. They will stop for a fee, but that early in the morning the stores might not be open yet. It be easy enough to later just walk across the street if you decide.
We buy wine at the duty free in Canada before we fly because the wine sucks at TTR unless it has changed since renos? We like to have some wine while getting ready for the evening