Each character was seeded by the father, then shaped by in-game events and a desire for some differentiation from the others. In the beginning, before I knew much about how BM worked, I figured my family would focus on wealth. Mercer is derived from "merchant," and striving for money and the Banker offices was the foundation for the first generation. My characters are named alphabetically as they are created.
Archibald, the eldest, happened to begin play in a theocracy, and became very pious; ultimately a zealot and a martyr.
Bernard began in the slow, secular colonies, and to contrast with Archibald became an open-minded seeker of a variety of meaningful philosophies.
Charles, to contrast with the older two, began as a brash warrior, but evolved and matured into a diplomatic leader and legendary hero.
Darla, the illegitmate daughter, began as an adventurer and had to earn nobility the hard way.
Edward is the son of Archibald. Furious about the circumstances of his father's fall and death, he roams the continents seeking only to fight.
Franklin is the son of Bernard. Having grown up posh and traveling through many lands, he began adulthood as a trader and courtier.
Geoffrey is the son of Charles. He lives in the shadow of his famous father's great achievements, and is on a quest of personal development to try to fill his father's shoes.
I do not draw from any resources for personality, preferring to let characters develop naturally from their upbringing and experiences. I have enjoyed the Showtime series, the Tudors, though, and the novel Jonathan Strange and Mr. Norrel as examples of noble behavior.
