Flew Etihad to uk with 5 month old, was fine I think the airlines are all pretty similar really have flown quite a few long haul though never Korean and all have had own tv with shows and games on it - think is fairly standard these days is only the shorter flights don't get your own screen in my recent experience. If want vegetarian specify when book the ticket, airline food never great but normally edible, vegetarian dishes often quite spicy though.