Info derived from imdb. Only roles 2013 and later being tracked.
Tarzan, Lord of the Jungle segment:
Robert Ridgely (Tarzan): died in 1997.
Jack Bannon (?): in Without a Ladder (2013).
Ted Cassidy (Phobeg): died in 1979.
Robert Chapel (?): last known acting role in 1980.
Linda Gary (various): died in 1995.
Joan Gerber (Queen Nemone): died in 2011.
Barry Gordon (?): in Forked Up (1 episode 2015), Teenage Mutant Ninja Turtles (2 episodes 2014); as Self: Turtle Power: The Definitive History of the Teenage Mutant Ninja Turtles (2014).
Hettie Lynne Hurtes (various): in School Dance (2014), Parts Per Billion (2014).
Alan Oppenheimer (various): in Fall of Grayskul: He-Man Fan Film (2015), Adventure Time with Finn & Jake (1 episode 2014), Foxcatcher (2014); as Self: TV's Nastiest Villains (2014)
Jane Webb (?): died in 2010.
New Adventures of Batman segment:
The Freedom Force segment:
Michael Bell (Merlin / Sinbad / Super Samurai): in Transformers: Devastation (2015 video game), Transformers: Rescue Bots (4 episodes 2015), Toy Soldier (2015), Community (2014), Lightning Returns: Final Fantasy XIII (2013 video game); as Creative Consultant: Sparks (2013).
Bob Denison (Hercules): last known acting role in 1988.
Diane Pershing (Isis): last known acting role in 2010.
Jason of Star Command segment (the only live action segment; only actors in episodes part of Super 7 noted):
Craig Littler (Jason): last known acting role in 1997.
Sid Haig (Dragos): in Bone Tomahawk (2015), Suicide for Beginners (2015), Zombex (2013), The Penny Dreadful Picture Show (2013), Devil in My Ride (2013), Hatchet III (2013); High on the Hog (2015; also Producer) in post-production; Abruptio (2017) filming; Razor (2015) in production; as Self: Groovey.TV's Celebration of Badassery Interview Series (1 episode 2015), Smoke and Mirrors: The Story of Tom Savini (2015), Adam Green's Scary Sleepover (2 episodes 2015), Quickies (1 episode 2015), I Am Santa Claus (2014), MovieCops (2 episodes 2014), That Hashtag Show (1 episode 2014), MoreHorror in Hollywood (1 episode 2014), Holliston (1 episode 2013); as Self, filming: Clapboard Jungle: Surviving the Independent Film Business (2016).
Charlie Dell (Professor E.J. Parsafoot): in Shameless (1 episode 2013)
Susan Pratt (Captain Nicole Davidoff): last known acting role in 2007.
James Doohan (Commander Canarvin): died in 2005.
Manta and Moray segment:
Joan Van Ark (Moray): in The 636 (2014), Watercolor Postcards (2013), Dallas (1 episode 2013); as Self: Beverly Hills Royal (1 episode 2015), Frogs: Buried in Frogs with Joan Van Ark (2015), Home & Family (1 episode 2014), The Nicole Barrett Show (1 episode 2014), Oprah: Where are They Now? (1 episode 2014), RuPaul's Drag Race (3 episodes 2013), Pioneers of Television (1 episode 2013), The Talk (1 episode 2013).
Joe Stern (Manta): no known subsequent acting roles.
Superstretch and Microwoman segment:
Ty Henderson (Superstretch): last known acting role in 1987.
Kim Hamilton (Microwoman): died in 2013.
Howard Morris (Lt. Buzz Tucker): died in 2005 but imdb lists him in Off the Beach (2013).
Web Woman segment:
Linda Gary (Web Woman): died in 1995.