I don’t usually touch Sunwing but it seems they are the only direct option to FPO. WS is going to operate all flights for Sunwing effective end of the month.
I am trying to figure out if I will get free checked bag for holding a Westjet CC. Sunwing agent said I was not the first person asking, but they did not have any specific guidance yet.

For my upcoming YYZ-FPO flight end of June, although Sunwing refused to give out the PNR, I was able to get it from Sunwing app (not website). WS website showed Econ P fare, but it can clearly identify the flight as part of a vacation package, and all add ons including seat selections, baggages etc. are blocked with a msg directing me to contact Sunwing.

I called WS and the agent added my WS # without any problem. The reservation now shows under My Trips, but MMB still shows vacation package flight and no add ons allowed.