Possible Clues:

• Parental pair in some families
• Half of a 1960s folk rock group
• Mamas' bandmates in a '60s group
• Half of the “Monday, Monday” singers
• Parents celebrated in June
• Half of a 1960s pop group, and what's found in half of this puzzle's long answers
• Half the "California Dreamin'" group
• Half the "California Dreamin'" quartet
• Half a '60s quartet
• June honorees