Melissa McBride (Carol) is also in The Mist, but she gets killed fairly early in the movie.
I think all three were brought into TWD by Frank Darabont, the producer of both The Mist and TWD.
In the comic, Morgan and Dwayne Jones do both show up again, but much later in the story, well after the survivors leave the prison and move on to other areas.
If you watch the ending of The Mist again (and it’s hard to do, I admit), you’ll see Melissa McBride’s character in the back of the Army truck, crammed in with a bunch of other people.