I'm not familiar with Eddie Dew. Victor Mature was a good actor: Whether as Samson in Samson and Delilah, Doc Holliday in My Darling Clementine, Nick Bianco in Kiss of Death, Demetrius in The Robe and it's sequel Demetrius and the Gladiators.
Anthony George I remember as the guy who replaced Mitchell Ryan as Burke Devlin in Dark Shadows. He also played Agent Cam Allison on The Untouchables, and Don Corey on Checkmate, as well as gust starring on many other TV episodes.
Katerine Ross is a wonderful actress: Etta Place in Butch Cassidy and the Sundance Kid, Elaine in The Graduate, also in The Legacy, The Final Countdown, The Shadow Riders, Conagher, The Stepford Wives, Shenandoah...Mrs. Sam Elliott is good in all of 'em.
And, of course, Magnum himself. Tom Selleck is a versatile actor: he can do comedy, he can do Westerns, he can do straight drama, he can do action. One of the best.