Yup, I did remember that SQ may serve food from the back too. But I haven't flown SQ in a while, just United. But I have never liked seating towards the back, more noise (engine or people) and less comfortable (turbulence etc). As for the noise part from the people, 777 has the lavatories towards the middle of the plane with only 1 at the back plus the gallery, while the 747 has 4 lavatories at the back with no gallery. I wouldn't expect the staff to be too noisy but I cant say so for passengers.