He was seen exiting the park at W. 85th. That’s not the right direction for NYC airports, but it is the right direction if he was going back to the hostel ~15 blocks from there, to get the rest of his shit or do who knows what. Obviously investigators know whether he went back to the hostel afterward, but that’s not been made public as far as I know.
As for Starbucks, I’m not going to get into your theories of lookalikes or whatever, but they claim to have tracked one single guy from the point he pops up at 57th/6th from the F train, to Starbucks (which is directly adjacent to the top of those subway stairs, so it would’ve been the first thing he saw) for his water and protein bars, then to the Hilton (still on 6th Ave), and ultimately to the curb on 54th near the Hilton where he waited for the CEO. Same clothes, build, backpack.