Here's an idea, a mother, father, two grown up children, a lodger and a wrinkly plus two people for the mum and dad to have an affair with, and a pet if you like. Any actor, living or dead.
Mother: Dawn French
Father: David Jason
Son: Harry H Corbett
Daughter: Sophie Winkleman
Lodger: Henry Winkler
Wrinkly: Arnold Ridney
Mother's lover: David Warner
Father's lover (femme fatale): Kylie Minogue
Pet: Hercules the Horse
(I think Harry H would be have to be younger than we knew him in Steptoe in order for this to work)