No every single flower will produce fruits. Also, if you want to increase productivity you must hand pollinate them.
Waste of time... Passionfruit is a weed! I get more fruit per day than anyone could handle.... Fredrick needs no hand pollination
Lucky, in El Cajon at least where ours grow, there are no carpenter bees and the natives just steal the pollen or nectar. Zero fruit without hand pollination,
My guess on the buds dropping off is too much/too little water, or too much fertilizer. I've seen it happen, but in the season that was described, they should be flowering.