Economy will be fine since the flight is only 14hrs

The flights in question are

BA0016 BA metal
or
BA7311 Qantas metal

I assume Avios and TP earning will be the same?

Is there a reason for choosing one over the other, eg food, drink, seat?

One of the persons travelling is BA Silver and should be able to chose seats on Qantas?
Are the Economy seats on Upper Deck the best choose?

With Qantas, will discounted uppgrade offers appear in MMB