thanks guys for your fast respond.
So which one should I go with? BA or Qantas? (the BA 100k miles credit card offer is nice but too bad I don't have any credit record

)
I haven't ask the class code but they'll be flying economic full rate. From Orlando to Dalas, then to Japan and final destination is Saigon, Vietnam.
That should be at least 15-20k miles per account. And since they only travel once every 4 years I could use those miles even tho I don't have any Oneworld's FF account

(well I do have a JAL mileage bank but with only 2k miles on it)