Benjamin means the "Southerner," and Ben-Oni "the inhabitant of Beth-On." It is even questionable whether the son of Jacob from whom the tribe was held to be descended bore the name of Benjamin.
Had the name of Esau not been preserved we should not have known the true name of the founder of Edom, and it may be that the name of the tribe of Benjamin has been reflected back upon its ancestor.
In Goshen, at all events, the tribes of Israel would have been distinguished by the names of their actual forefathers.

They would have been "the sons" of Reuben or Judah, of Simeon or Gad.

But they were all families within a single family.

They were all "Israelites" or "sons of Israel," and in an inscription of the Egyptian king Meneptah they are accordingly called _Israelu_, "Israelites," without any territorial adjunct.

They lived in Goshen, like the Bedawin of to-day, and their social organisation was that of Arabia.
The immediate occasion of the settlement of Israel on the outskirts of Egypt was that which has brought so many Bedawin herdsmen to the valley of the Nile both before and since.