Flew Y on A380 and B787 a few days ago.
I booked 27D upper deck hoping to get 4 seats, no luck 27G was taken.
I don't see any advantage to have 4 seats for two unrelated passengers.
Window sides most rows had 2 seats occupied, I got the gold FA welcome speech with food pre-selection. Upper deck not full. Seems any one can book upper deck with OLCI, status holders have next seat blocked until high load I guess.
Choose window seat on the B787, middle seat was free, aisle seat other gold passenger (we both got the FA welcome speech and food selection). Again no luck: middle row had 1 pax for 3 seats, behind me also 1 pax for 3 seats.
Any way, return flight in J a few days from now, I am not a Y aficionado...