I don't have much to offer re: ranking of these airlines, but if the OP's wife will be paying cash and has -- or can quickly acquire -- the Amex Platinum card, then substantial savings might be found via the Amex International Airline Program. Details here:

https://upgradedpoints.com/travel/am...rline-program/

("American Express International Airline Program: The Little-Known Secret to Huge Airfare Savings")

I note that people have recently reported sign-up bonuses of up to 175,000 MR points on the Amex personal Platinum; charging two Business Class roundtrips to the card would likely go a long way to meeting the spend requirement for the sign-up bonus. Note that the cardholder must be one of the people traveling in order to qualify for the IAP discounts.