In Hawaii we (people not of Japanese origin) heard and occasionally used these honorifics. I primarily became aware of them because of their occasional use by my Judo sensei's and their occasional use at judo tournaments.0-, Go-, Dai-, sama ...
So my youngest sister and half-brother probably wouldn't know these honorifics (except possibly O-). My older sister would know two, maybe three because she studied Polynesian dance and was thus around older Japanese-American Aunties as well as Hawaiian and other Polynesian Aunties.
We sat seiza at my judo club. Some Zen Buddhists on the East Coast definitely sat seiza even during retreats 18 years ago for sure. I can no longer sit seiza because my feet changed somehow about ten years ago (one day they essentially became numb).Sitting in seiza, for instance. Most Buddhists, certainly Buddhists outside Japan, don't sit seiza.