Tenors of Rock seems to get good reviews and seems to be something they would both enjoy, perhaps the wife more.
Zumanity I hear is good but may be more suited for husband and wife than mother and daughter.
Ka' I've heard mixed reviews.
O is my first choice. With all of the Cirque shows on sale this seems to be the time to do it. If I stay away from the seats that are described as having limited views should the moderately priced tickets be fine?
World of Water at Rio. Is it a poor man's O?