The following information can be gained with a Streetwise check:
DC 15: The Rivenstaves have been in Harrowdale for more than a century. They trade mostly in the Moonsea area, having established extensive trading contacts there. Lucus Rivenstave is one of the Seven Burghers of New Velar.
DC 20: Some rumors say the Rivenstaves secretly worship Bane, but the family denies this.
DC 23: Anna Rivenstave is now the real power behind the Rivenstave family as Lucus is too sickly to really do anything.
DC 25: The Rivenstaves have a conflict with the Nenthyns regarding the border of the Nenthyn estate. This has rather soured their relations, and they often take opposite stances in a dispute.