Andy Garcia’s charater in
Just the Ticket - I’m actually not sure if this is the movie I remember seeing about a guy who is trying to score tickets to the Pope’s visit to NYC so he can scalp them.
A major character in Fast Times at Ridgemont High is a scalper, although I wouldn’t say he’s the lead.
Character Performer at a theme park?
Not lead role, but in Wayne’s World, a big part of the plot includes the world’s best roadie.
Gynecologist- Dr T and the Women with Richard Gere
Tennis umpire?
Ron Livingston would have made a great Goofy in Swingers.
The movie Snow Day features Chris Elliot as a snow plow driver - he’s the villian trying to get the roads cleared so the kids don’t have a two-day break.