Charles Frank, William Christopher, and Susan Blanchard all appeared on M*A*S*H (1972). Frank and Blanchard guest starred while Christopher was, of course, Father Mulcahy.
The references to Edgar Allan Poe by John Astin are interesting. In his native Baltimore, Astin is very well known portraying Poe on stage in a show called "Once Upon a Midnight"
Laurence Luckinbill's (Howard Crane) first appearance of four during the years playing different characters.
First appearance of Three for Lee Meriwether (Grace Overholt) who would play three different characters during the years.