This wiry, energetic, black actor is from the busiest family in show business. The youngest of the ten Wayans children, Marlon made his feature debut in brother Damon's action comedy showcase "Mo' Money" (1992). As Seymour, the younger brother--and partner-in-crime--of the con man protagonist, Wayans displayed an engagingly manic comic personality. His slender body, expressive features, and triangular face lent a stylized cartoonish quality to his performance.Wayans had appeared in several national commercials before he spent three years as a regular on the sketch comedy series "In Living