Info derived from imdb. Only works 2013 and later being tracked. Only actors in 2+ episodes noted.
Bob Denver (Gilligan): died in 2005.
Alan Hale Jr. (Jonas 'The Skipper' Grumby): died in 1990.
Jim Backus (Thurston Howell III): died in 1989.
Natalie Schafer (Mrs. Lovey Howell): died in 1991.
Tina Louise (Ginger Grant): in Late Phases (2014); last previous known acting role in 2004 but Tapestry (2016) in post-production.
Russell Johnson (Professor Roy Hinkley): died in 2014
Dawn Wells (Mary Ann Summers): in The Bold and the Beautiful (1 episode 2016), She's Still on That Freakin' Island (2015), Life Interrupted (2015), This Is Our Time (2013); as Self: Home & Family (1 episode 2015), Svengoolie (1 episode 2015), Steve Harvey (1 episode 2015), Today (1 episode 2014), Chopped (1 episode 2013), Marie (1 episode 2013), Survivor Stories with Dawn Wells (2013); as Self, post-production: Surge of Power: Revenge of the Sequel (nd).
Charles Maxwell (Radio Announcer): died in 1993.
Rest Various Unless Noted:
Vito Scotti: died in 1996.
Mel Blanc: died in 1989.
Janos Prohaska (Ape): died in 1974.
Eddie Little Sky: died in 1997.
Russ Grieve: died in 1980.
James Start (Clarkson): in Catching Faith (2015), Beethoven's Treasure (2014).
Hans Conried (Wrongway Feldman): died in 1982.
Denny Miller: died in 2014.
George N. Neise: died in 1996.
James Spencer: last known acting role in 1971.
Chick Hearn: died in 2002.
Gilligan’s Planet (1982-1983):
Animated version of above.
Bon Denver, Alan Hale Jr., Russell Johnson, Natalie Schafer, Jim Backus (same roles); Dawn Wells (same plus Ginger Grant): see above