We're canonblind to the canon, so we may have misunderstood or missed information about the character. From looking at the wiki, our initial interpretation was the character's personality and history is mostly set by the player's choice in the beginning and then rest was left blank.

But if they have either a "default" scenario, or if they are actually following a storyline route and you're just picking defined answers at certain story steps that would reflect a specific personality, then you are correct that they would be appable.

Since we're not familiar with the canon, could you explain a bit more how it works? Especially since this seems to be an interactive text game.