An even simpler solution would be to allow the player to select either one two or three of the characters from the list. This would allow a reasonable freedom of choice without compromising the original design intention and would obviate the need for any sort of character generation.
As a side issue to this, the introductory narrative refers to ‘you’ and three comrades in arms – making four. So where is the ‘you’ referred to, as you only get three starting brothers?
Also it suggests that the three fought in the shield wall with you, which puts them as soldiers. Clearly, a lot of the potential starters are not soldiers, so the beginning doesn’t really fit the narrative. Maybe that could be changed to ‘have fought with you for the past few months’ instead.
I would prefer the ‘you’ to be one of the three initial brothers, picked randomly or otherwise, rather than being an invisible presence.