How do we know that Corvinus Gaunt was in Slytherin? There's no references that indicate that was Corvinus's house.
I removed Cadmus Peverell from the list of Corvinus Gaunt's relatives, because there's nothing in the books or on Pottermore to indicate those two were related. Marvolo Gaunt, born hundreds of years after Corvinus, was also descended from Peverell, but that doesn't mean Corvinus was. If anyone knows of anything canonical to indicate a relationship between Corvinus and Cadmus, please let me know.