Thanks all for the advice. Mostly as I thought, but Koru Flyer is correct that QF F lounge in SYD will be available to us, since wife and I are flying first, and I can guest daughter in - I had missed that.
NateOz, so the Gold lounge for OWS in Doha isn't a oneworld lounge? I'm a bit worried now about getting split up, so perhaps paid access to either Al Safwa or Al Mourjan is the best bet.