My opinion is, no. Others will say you can get a boat board such as the Hyperlite Broadcast or Liquid Force Doum. Can both of them ride these? Sure, but neither will be proficient. To me it's as simple as anything else. You wouldn't have them use the same size snow skis, tennis racket or running shoes, would you?
Check out a P5 Luv or Prop for your wife and a Scamp for your daughter or inland Surfer Caro for the wife and Ooze for your daughter.