The company included more swords than Catelyn would have liked. Three by the fire wore the red stallion badge of the Brackens, and there was a large party in blue steel ringmail and capes of a silvery grey. On their shoulder was another familiar sigil, the twin towers of House Frey. She studied their faces, but they were all too young to have known her. The senior among them would have been no older than Bran when she went north.
I think the first "would have" is backshift of "would", meaning "wanted".
I think the second "would have" has an implied condition: if it had been the time when she went to the north, the senior among them would have been no older than Bran.