For this one, I don't know, so can't say.
Does she already have an account with Avios/Qpoints already?
You probably know, with QFF, you can't transfer points from it to Avios, but I think family transfers might be the way to go, if you want to open an account for her, if she does not have one, and then, get her to put QFF into any OW booking she has, till she has enough QFF points in there, then sweep the QFF points to you.
A lot of things to consider.
Ultimately, to sum up, if she is going to fly with BA/QR more in future, within Europe (BA), and where ever she needs to go with QR where BA doesn't fly, in future, go with that one, ie, Avios.
One option to build up Avios, if she wants to, is to fly PER - SYD on the way back with QF, putting her BA # into booking, then BA up from SYD - SIN - LHR.
QR does not carry QF flight numbers, but just that its in OW, otherwise, the earn rate would be very low, ie, EK if it does not have a QF flight number.
Also need to check what status tier QR gold/silver is in OW, and if its high enough, that might already give lounge access, internationally.
Sorry for the waffly.