Unfortunately for me, Batman 667 follows the template of Agatha Christie's And Then There Were None and features primarily characters taken from World's Finest 89, neither of which have I read. So I won't speak to any parallels among these. Still, Morrison, with nods to Christie, crafts an enjoyable first chapter for this mystery, with the Club of Heroes so endearingly pathetic that it's hard to imagine any of them mustering up the cojones to commit murder, although one of them will most certainly be fingered as the killer.
Page 1: Aside from any higher, more abstract meaning, red and black are the colors of gambling (we see the Joker playing cards later too), something opposed to Batman, for whom risk is eliminated by intense preparation
Page 4: The Knight is a pet character of Morrison's. In addition to their first encounter in Detective 215, Cyril Sheldrake appeared with Batman in both Morrison's JLA and JLA: Classified. In Batman 655, he failed to return Bruce Wayne's phonecall, a call ostensibly to discuss this meeting of the club.
Page 5: Batman gestures "this high" with his hand, just as Damian did in 658 and as Jezebel will do 681. Not sure about the meaning of this, but it seems to appear too frequently to be a coincidence.
Page 6: The Musketeer basically foretells the whole story of RIP, "locked in an asylum with two of my greatest enemies alongside an army of gibbering homicidal freaks." and later "I never have to fight crime again." Amusingly, the Musketeer hauls in millions from this story, perhaps channeling some of Morrison's wishful thoughts about RIP.
Page 8: Legionary apologizes to Man-Of-Bats for "last time", which we see in 668 and 669.
Page 10: The Dark Ranger summarizes his self renovations, more on this later.
Page 12: Batman, grim as a gravestone, dwarfs the other members of the club, who are awe struck by his presence.
Page 15: The mystery man costumes himself in Mayhew's skin, like Orlando from The Invisibles and like Dr. Hurt brags to have done to Mangrove Pierce in 681. The grotesque act of wearing another person's flesh stands as a physical counterpart to possession of the mind, wherein one temporarily wears a body to suit their generally evil ends, a major hang up of the Devil's. Actual mental possession shows up in the largely overlooked Ra's Al Ghul arc.
Page 15: Note the painting on the wall. From Thom Young's review on comicsbulletin:
Fortunately, Timothy Callahan, the author of Grant Morrison: The Early Years was able to identify it for me. It’s The Triumph of Death by Pieter Bruegel the Elder—a painting that shows people of various social classes, from peasants and soldiers to aristocrats and clergy, all dying indiscriminately.Page 18: "And don't eat any more food," Batman eschews all food in Morrison's run, whereas secondary characters like Robin, Legionary, Musketeer, and Man-Of-Bats can all be seen noshing on one thing or another at different points in the run. Funnybook Babylon's Chris Eckert theorizes about this apparently annorexic Batman, and I'll spit out my own theory in the post for 675.
Page 20: Strangely, Morrison blows his best red herring, the Legionary, right at the beginning of the arc. Why was the Legionary his best red herring? Because an evil impostor Legionary infiltrated the Batmen of All Nations in their first appearance in Detective 215
Last Page: "Advantage evil, place your bets with the Black Glove." An anonymous friend of David Uzumeri's likens gambling on good and evil to God and the Devil's wager over the loyalties of Job. I believe it. The complete devastation of Job's life in the Job arc of the Bible (kidding) definitely resonates with what happens to Batman later in Morrison's run.