looking at the way CX schedules their planes, as long as there are some F cabins on the longhaul, there will remain some Asian F services as well. The best F flights in Asia are the Japan routes and the evening service 716 SIN-HKG.

There is no F pass. All the oneworld "pass" products are in Y only.
Discounted F fares are available from many European destinations on the local CX websites. Check "Online fares". Incidentially, FRA seems to be the cheapest departure point.

It is my experience (as CX Gold and CX Diamond on HKG-TPE, HKG-NRT, TPE-NRT, SIN-HKG, HKG-KUL) that a fullfare J ticket will almost always get you a seat in the F cabin on Asian flights. I find it makes more sense to buy J (not D or I!!!) than A or F.