Old Bat
It's probably not the definitive answer you seek but Australia's East-West Airlines certainly did have a Hostess on their Hudsons from 1949. These Hudsons were effectively Lockheed 14s, or if you prefer, ploughshares converted to swords and back to ploughshares.
As an interesting aside, at a recent historical conference in Australia, a (female) "academic" presented a paper in which she claimed that (male) engineers at East-West Airlines had constructed a box across the cabin of the Hudson so that the hosties would have to hoist up their skirts for the entertainment of the (male) passengers. She was informed by robust interjection that said "box" was holding the wings on!