Misc: In 1942 Harrison ---------- actor (Star Wars, Indiana Jones, Frantic), born. ?

Questions

This co-star of "The Carol Burnett Show" hit #1 in 1973...?

This group song the 1978 #1 "Baby Come Back"...?

This man sang lead for the 4 Seasons comeback #1 hit in 1976, "Oh What A Night"?

This singer's "Escape (The Pina Colada Song)" was the last #1 of the 1970s...?

This song spent more weeks at #1 than any other in the 70s?