I play Pollux Black, their 2nd born child but 1st born son. The link has more links to his history, along with Cassiopeia (1st born) and Dorea's (4th born). Pollux has the utmost respect for his parents, and would literally do anything for them. Cassie and Dorea are both children in the game, so as long as Cygnus or Violetta are older than 18, they would reclaim guardianship over the girls. At the moment they are living with Sirius Black and Morag MacDougal, which Pollux is not a fan of one bit. There are a whole whack of Blacks in play, so there is a rather large potential for interaction.
See his history for more details, or contact me for potential plot!