And can I buy qantas flights using part Asia miles and part QANTA ff points
Hi and welcome,
As far as I believe, you cannot use a mix of two different airline points to pay for a single flight.
If you have sufficient points to cover 2 flights or 1 flight for two passengers, you could use Qantas flight to book for 1 and Asia Miles to book for the other (assuming both programs see the award space for the same flight(s).