Is this Werewolf! (1979), a collection of werewolf stories edited by Bill Pronzini...?
One of the stories in the collection is "There Shall Be No Darkness" (1950) by James Blish, which I suspect is the second of the three stories you described. Note that some printings of this story (such as this one) don't include the part you described, but the longer version published within the aforementioned collection does. You can read the longer version of the story here, but here's a relevant excerpt:
Jarmoskowski's smile became a little mocking. "Go into a great railroad station some day—Waterloo, or a Metro station, or Grand Central in New York; get up above the crowd on a balcony or stairway and look down at it in a mirror. We do not show in a silvered mirror. Or if you are in America, find one of the street photographers they have there who take 'three action pictures of yourself' against your will and try to sell them to you; ask him what percentage of his shots show nothing but background."
Another story in the collection is "A Prophecy of Monsters" (1954) by Clark Ashton Smith, which I suspect is the third story you described. You can read the full story here, but here's a relevant excerpt:
The path ahead was heavily shadowed. Dimly, moving fast, the walker appeared in the shadows. He seemed to be all that the watcher had surmised from the sound of his footsteps. He was tall and well-shouldered, swinging with a lithe sureness, a precision of powerful tendon and muscle. His head was a faceless blur in the gloom. He was hatless, clad in dark coat and trousers such as anyone might wear. His steps rang with the assurance of one who has nothing to fear, and has never dreamt of the couching creatures of darkness.
Now he was almost abreast of the watcher's covert. The watcher could wait no longer but sprang from his ambush of shadow, towering high upon the stranger as his hind-paws left the ground. His rush was irresistible, as always. The stranger toppled backward, sprawling and helpless, as others had done, and the assailant bent to the bare throat that gleamed more enticingly than that of a siren.
It was a strategy that had never failed ... until now ...
The shock, the consternation, had hurled him away from that prostrate figure and had forced him back upon teetering haunches. It was the shock, perhaps, that caused him to change again, swiftly, resuming human shape before his hour. As the change began, he spat out several broken lupine fangs; and then he was spitting human teeth.
The stranger rose to his feet, seemingly unshaken and undismayed. He came forward in a rift of revealing moonlight, stooping to a half-crouch, and flexing his beryllium-steel fingers enameled with flesh-pink.
"Who - what - are you?" quavered the werewolf.
The stranger did not bother to answer as he advanced, every synapse of the computing brain transmitting the conditioned message, translated into simplest binary terms, "Dangerous. Not human. Kill!"
The first story you described may be "The Werewolf and the Vampire" (1975) by R. Chetwynd-Hayes, but if so, it isn't included within this collection. Regardless, you can read the full story here, an extended synopsis here, and here's a relevant excerpt:
The Reverend John Cole had been bitten by a baby werevamp, nipped by a female vampire, and clawed and bitten by a full-blooded buck werewolf.
Only the good Lord above, and the bad one below, knew what he was.
