KUL is close to SIN and YUL is close to JFK; QF doesn't fly to either city on the way to OZ from UK. Clearly the holiday packages include non-QF flights (and non-OW in the case of Malaysia). Presumably the choices are to compete with the alternatives (I'm sure they are matching what some other airlines are offering; the LAX routing would seem to be to match NZ, perhaps why they don't include SFO).