I have no idea how best to introduce myself into this string of discussions. My father's mother (Torbe) and father (Khait) both immigrated from Linkuva in the 1890's (think I have that right), as did his grandfather earlier (and possibly also his grandmother), all to St. Louis, MO. His grandfather adopted the name Rosenthal, thus the family name here in America.
Yes, to my knowledge Traub is the surname some Torbe siblings adopted upon emigration from Linkuva to Johannesburg SA. My wife and I actually traveled to Clearwater FL to meet and spend an afternoon with a Torbe 2nd cousin who had immigrated from Johannesburg to Clearwater maybe 20 years ago. I had discovered him through another highly genealogically-talented non-blood cousin I'd discovered earlier on Geni, she and her husband driving down from Gainesville FL to make it a very memorable 4-party new-family meet.
There is a large tree of your family on JewishGen, I think in much more detail than what you posted here. Send me an email and I can send you a screenshot. Diane@lawgal.com
Max, I passed your comment re "transferred to Joniskells from Linkuva ..." onto Ellen Robin Dickstein here on Geni, a relative on the Torba side from Linkuva, here's her comment: "Not sure what information that Max is looking for. Does he want to know about his great grandfather or why he was transferred to Joniskelis from Linkuva? Also, I wonder if he was in the military. I think that there were restrictions or where Jews could travel and maybe live. And there were these internal passports I think. I will forward to my cousin Ben and see if he knows."
Does any of that peak your interest? Ellen's here on Geni and quite knowledgeable (compared to me, a downright expert).