I am sure it will be confirmed here, but the majority of the recent DSC promotions have limited the eligibility to QF flights only.If you are negotiating to get DSC on your BA flight, you are out of luck

My in-laws flew LHR-DXB-BWN-PER nearly 10 years ago now. Cheap J fare so they were happy. They had an enforced layover in BWN for about ~18 hours or so as the Sultan commandeered their aircraft. They weren't fussed but interesting nonetheless

There are other simple ways, do you shop online at places like eBay?

Unless being granted entry by CoS or being guested, why would there be QP members in the lounge anyway?

The actual photo is of the -300, which is the features the fully refurbed Y product. The -200 which is the variant that features on most of the 330 operated domestic flights currently has 3 different Y products (iPad, EBG/L, and Seat back IFE).