When the heavenly whippet looks in Charlie's records, his mother and father are named "Loni" and "Burt", and look like canine versions of Loni Anderson and Burt Reynolds (who were together at the time.)
Steven Spielberg was going to be the executive producer of this film and have it released under the Amblin banner, but left the project after creative differences with director Don Bluth while they were making The Land Before Time (1988).
The book on Charlie's life reads Charlie B. Barkin September 13, 1937 mostly German Shepard but also part collie, part great Dane and part retriever in short a bit of a mutt. the rest is difficult to make out but may mention how he doesn't have much goodness or loyalty, tends to be on the greedy side, but a small section does mention strong love.possibly foreshadowing his change from bad to good.
The illustration on the War and Peace book that Charlie "reads" to Anne-Marie has the caption "General Pomeroy is shot." This is a reference to lead animator John Pomeroy, who is also a military history buff.
Carface Caruther's other thugs in The Mean Street Dogs gang have names including Otto and Thunder. Otto is the big, mean dog who bites Charlie's foot after he gets tied to the anchor. However his name is never mentioned and he never has a dialogue in the movie until he and the rest of The Mean Street Dogs later appear in the All Dogs Go to Heaven: The Series: Magical Misery Tour (1997). He is played by the voice of the talented, comical Carlos Alazraqui in that episode. Rumors say that Thunder happens to be the short, fat, bearded green bulldog in orange tank tops. His name is mentioned by Killer during the scene where Carface is angry when he has found out that Anne-Marie has let his Casino. He explains to Carface, "But, boss, it wasn't my fault. To be perfectly honest, you see, I--Uh--B-B-- Thunder was on duty. Take it up with him". Thunder has no dialogue in the movie either until he appears in the All Dogs Go to Heaven: The Series: Magical Misery Tour (1997) as well.
The scene with the alligator in this movie has since created the trope "A Big Lipped Alligator Moment." A Big Lipped Alligator Moment is a scene that happens out of nowhere with no build-up, is strange when it happens in context, has little-to-no help to the plot at all, and is never mentioned ever again. People often think the scene isn't a Big Lipped Alligator Moment because the alligator appears later in the movie to kill Carface off-screen.