Elwin Ransom
Elwin Ransom may be based on C. S. Lewis' friend J. R. R. Tolkien ("Elwin" means "Elf friend" in Anglo-Saxon), though he seems to have autobiographical elements. In "That Hideous Strength" Ransom, with his royal charisma and matter-of-fact breezy acceptance of the supernatural, appears less like Tolkien than like Charles Williams (or some of the heroes in Williams' books).
Cyril Beeson
Beeson attended City of Oxford High School for Boys, where his best friend was T. E. Lawrence (better remembered today as Lawrence of Arabia). Lawrence called him by his nickname of "Scroggs".