be aware of one thing , when you buy a ticket from OK's site, you will not be able to see the booking code before purchase

the only way is to book it from a physical travel agent and ask him to check the code before validation

Or by using ITA matrix in order to compare with the price you get and guess what you will receive

by experience i can tell you that only flex and business fares will be considered as qualifying , but the prices are so high , that if FB is your main concern book the same trip from AF/KL/AZ with a layover in order to save money and get more miles because OK is not worth such amount of money . Its like easyjet but 3/5 times more expensive