The cover image is not related to either story in the issue.
New story.
In the story's first panel, it would appear that Daphne's and Shaggy's dialogue balloons are pointing to the opposite character. Daphne should have the first balloon, while Shaggy should have the second and fourth. The third balloon, pointing to Scooby-Doo, is positioned properly.
Parodies of notable genre figures abound: "Woody K. Wackerstein" = Forrest J. Ackerman, but is also drawn to look slightly like comic book legend Stan Lee.
"Walt Palace" = Gimmicky horror film producer William Castle.
"Eddie Allenshmoe" = Historic horror author Edgar Allen Poe.
"I.M. Creepy" = Harry Potter author J.K. Rowling (?), if only in the pronunciation cadence of the character's name.
"Ron Zamboni" = Horror makeup master Tom Savini - with an unnamed assistant drawn to look like a cleaned-up version of makeup master and producer Greg Nicotero.
GOOD BITS: A tour de force of genre humor by writer Sholly Fisch and the story's artists...
The "Gort" cosplayer parodies the immortal phrase "Klaatu barada nikto" from "The Day the Earth Stood Still" as "Hava Nagila Nicto" - referencing the traditional Jewish folk song "Hava Nagila".
The "cosplayers-as-aliens" reveal themselves as human to a scared Shaggy and Scooby (ever steeped in their own tropes):
SHAGGY: "Oh, I get it! They're like COSTUMES! I'll bet you guys are trying to STEAL somebody's inheritance! Or are you, like, PIRATES trying to cover up your SMUGGLING OPERATION?"
COSPLAYER: "Huh?"
VELMA: "Actually, I think they're science fiction fans dressed up for fun."
Scooby gives a thumbs-up to a kid in a Scooby-Doo T-shirt.
THREE movie posters on display - in the SAME PANEL - represent the same 1950s sci-fi/horror poster trope. One shows a bulge-headed alien carrying off an unconscious woman. A second, in a parody of the influential 1956 film "Forbidden Planet" titled "Don't Go Here", shows a Robby the Robot-like automaton carrying off an unconscious woman. The third shows a werewolf (you guessed it) carrying off an unconscious woman.
Fred is in his "ascot-less" outfit, as seen in the TV series What's New, Scooby-Doo? (2002-2006), as the original printing of this story was influenced by the run of that series.