Seems like (based upon his dress), Caleb and Lilith could either be from the early 1900's (Wild West era), and Lilith just adopted 80's+ fashion and stuck with it, both are from the late 1900's and Caleb just dresses flamboyantly, or Caleb is from the early 1900's, and Lilith is from the late 1900's.
They could either be half-siblings (from one vampire), blood-siblings (from two vampires), or adoptive/chosen siblings (no blood relation). If they had the same sire (or at least a common goal/enemy), it would make sense.
If you take the trailers as "word of god", then the Vatores are off-shoots of the rebellious vampires, and are also from the 80's. Lilith just dresses like a goth-punk, and Caleb likes being stylish.
