I have never dealt with the older family members, but a lot of college students a a couple in DOD. Obviously my contact is more limited than yours. I am not sure on your 2nd and 3rd generation though, most of the Hmong immigrated to the United States in 1976 through 1978. That is roughly 32 years ago.
sorry, there are 3 generations living here that speak little to no english, from my experience is that only if their parents were born in st paul, they speak english, of course this is not a scientific study, just observation. Being a “young” single white guy in their neighborhood, i am always the beneficiary of their culinary delights!