Hi, welcome to FT Australia_home!

As far as I know, the last few rows don't add any leg room. If you're flying alone, then the added advantage of a pair of two seats doesn't help.

My first choice for leg space would be emergency exit (aisle and middle) seats. The window ones have the door in front and the curve of the aircraft is not nice if you are tall. Ask for these at check in.

Second would be the bulkhead seats. The aisle is better because you can stretch your legs into the front beside the bulkhead.

I'd always choose aisle over a center seat though. The G seats are great because if you're right handed, you can eat without having to constrain your arm.

Can't comment on ZRH- Oz prices, but doing it on EK probably gets you Silver, so that's a good deal. Etihad only flies to GVA, QR has a limited network to Oz. SQ is an option, but probably more expensive.

Hope that helps.