Crossover Covers: Batman/Hellboy/Starman (with Some Notes on the Knight Family in the CU)
In his 1980s series All-Star Squadron, Roy Thomas established that Ted Knight, the original Starman and father of Jack Knight, the Starman who appears in this story, was the cousin of Sandra Knight, aka Phantom Lady, one of several characters DC acquired from the defunct comic company Quality. Phantom Lady is in the CU through two crossovers: "The Olympic Saboteurs," a story from the Fox Features incarnation of Phantom Lady where she refers to Sherlock Holmes in a context that suggests he is a real person, and a story featuring her successor in Action Comics Weekly that reveals that one of the former students at a university run by Sandra is Mrs. Emma Peel of The Avengers fame. Since Ted and Sandra Knight both have CU counterparts, I'm inclined to say their genealogical relationship applies to those versions as well as their DCU equivalent. It is worth noting that Mrs. Peel's maiden name was Knight, and her father was Sir John Knight. However, Art Sippo's story "How Art Thou Fallen from Heaven, O Lucifer" depicts Sun Koh, "the Nazi Doc Savage," having sex with a married MI5 agent named Lady Felicity Knight. Art has confirmed for me that Emma Knight-Peel is therefore Lady Felicity's illegitimate daughter by Sun Koh, and therefore Mrs. Peel has no actual relation to the Knight family.