LH Y to me is the worst on the list. The only perk is the free booze. The seats recline nearly all the way into your lap, and you can't get advanced seat assignments.

I'd personally go with either LX or AC (assuming you don't get E+ access with UA which would obviously be the most comfortable). Also, although you didn't list it, SQ flies JFK-FRA where you could connect to something else.

Chris