What's the Kennection? #65

The Brazilian electric is the smallest, and the oceanic manta the largest, species in what fish family?

One seat at a Jewish seder meal is always left empty in case what biblical prophet decides to drop by?

What Winston Graham bestseller was adapted by Alfred Hitchcock into a thriller starring Tippi Hedren and Sean Connery?

What code for missing children in public places was named for the son of America's Most Wanted host John Walsh?

What title character of a 1986 Woody Allen movie has two sisters, the insecure Holly and the restless Lee?

What's the "Kennection"?