Since Mr Al Baker, who rules over Qatar Airways and the QCAA has not yet replied to your post, I will try to answer your questions.
The QCAA issues licences based on the licence you bring with you. That is, a recognised ATPL will result in an issued Qatari ATPL. CPL = Q CPL, etc. (At least I think this is the case from what I have been told?) They are supposed to follow JAA.
I wasn't aware the A300's are second-hand? In any case, the 330's are planned to replace them. However, some will most likely remain in freighter config.
Standing by for incoming if I'm wrong!