To elaborate a little:
BC works with archetypes that are a little like OW's specialities. For choosing an archetype, you get a set of skills and talents, basic gear and a special ability. Further progression is not handled by speciality (apart from only psykers being able to buy further psyker-y stuff), but by your dedication to a particular deity (or lack of it). Thus, every character can theoretically buy anything.
Regarding archetypes, there are 4 CSM and 4 human ones in the core book. The CSM ones are Champion (leader archetype, can lend others his bonuses when it comes to using
Fate Infamy Points), Chosen (warrior archetype, can better inflict Righteous Fury Zealous Hatred), Sorcerer (psyker archetype, can... um... do psyker stuff) and Forsaken (scoundrel archetype, gains bonuses for acquiring gear - this is often houseruled as the bonus is kind of meh in comparison to the others). All of the archetypes contain basic CSM stuff so your Sorcerer will still be able to wield a boltgun.
There are also the advanced archetypes of the Tome line of books, with every book depicting two further human and two CSM ones, that come with skills, talents, gear and a new special ability. Those archetypes are created with more XP than the basic ones, so mixing them with basic ones can be problematic. That being said, there's a Night Lord archetype in the Tome of Blood. However, there's only one such archetype, meaning that if you use it, your entire group starts out with what are essentially slightly accentuated copies of the same character.
What I would suggest is using the basic archetypes so you get a diversified warband and then making the Night Lord special abilities (Spectral Haunter, gives bonuses for fighting in darkness; Terror Tactics, grants the Night Lord and allies a Fear Rating when they spend time terrifying a populace) available as tier3 talents.