Agree on OS - but mostly for food and wines. - my biased rating: OS>LX>LH

OS’s seat is similar to LX. If you don’t mind sitting next to someone (as you mention travelling with your daughter), the seating pattern in which LX and OS feature single seats becomes less relevant. I for one find LH’s seat more comfortable. - my biased rating: OS=LX>LH (for pattern); LH>=LX=OS (for comfort).

Service-wise it’s a wash between the three and you can have more or less involved crews at any of them. For friendliness I seem to luck out on OS and LX slightly less than others, but no really bad experiences either. - my biased rating: LH>OS>LX

Planes: LH gives you a chance of the upper deck on the 747 - even though to PVG I believe it‘s only a 744, not the more modern 748. OS‘s 777s are well maintained, but getting old.
LX‘s 777 are more modern. - my biased rating: LH>LX>OS.

All said, I‘d go with price and schedule first. All being equal, maybe a slight notch in favour of OS.