Ok one last set of clues because you guys are all around it and sooo close
Eternity; my meaning is been around forever in cricket and still is in a more famous role(still around and pretty healthy still, not quite as long as Richie Benaud!)
fraternity; i mean brothers in the cricketing fraternity.
No questioned paternity, so they both come from the same father..they are actually also brothers.
Captains courageous; pretty obvious although not both national captains.
into countries as strangers; the biggest clue! which most have misinterpreted, they both left their homeland to live and play cricket in a foreign country.
one brother is loud bold and kind of likeable.
the other is quieter, not well known.
so you are looking for two brothers, both of whom played cricket and captained their regional if not their national team (im sure the famous one did), one of whom is in a fairly famous role in wider cricketing circles (everyone will know him). One brother only played a very small number (single digit) of tests for his adopted country, the other more famous played many tests and is well regarded test player of his time. The famous one is outspoken, the other has hardly ever been heard from again in cricketing beyond his role as captain of his regional side.
ok ill give the answer at the end of my day which is in 8 hours time if noone guesses, but im sure someone will now. In my opinion Puddleduck has come closest with the Benaud's.