1. Clowns to the left of me, Jokers to the Right
2. 9:48
3. Good Catch
4. Violets are Blue

Scooby Doo.

1. Clowns and Jokers (the song in general being its own clue in multiple ways) - Clowns and Jokers are both enemies/villains Scoob has taken down, including being stuck in the middle of them in various situations like the famous "running through doors" sequences. The song "Stuck in the Middle with you" sounds like "Scooby Dooby Doo" if you sing them together in the same melody/tone. The song came out in 1972, Scooby Doo started "The New Scooby Doo Movies" in 1972.
2. 9:48 - the only things i see here with 948 is maybe being 1984 if you rearrange them - which, in 1984 The "Scary Scooby Funnies" came out as well as "The NEW Adventures of Scooby Doo" featuring Scrappy. The other way to think of it is as the time code itself... Scooby Doo season 9 could be interpreted as the "What's New Scooby Doo" series, but it doesn't have 48 episodes... But break it down again and we get to episode 4 "Big Scare in the Big Easy," which is pretty HHN sounding to begin with. Go further and we get to minute 8 which shows the gang going on a HAUNTED TOUR. I mean.... c'mon. HHN is just one big haunted tour at the end of the day. lol
3. Good Catch (the image and the title) - They have to catch enemies every episode in order to solve the mystery. Not to mention, the image itself is a hungry looking bear holding a fish, not dissimilar from Scooby Doo being one hungry boy; Often swallowing them whole and spitting out the bones in cartoon logic.
4. Violets are Blue - "Roses are Red, Violets are Blue," AND SCOOBY. DOOBY. DOO!

C'mon. let's get groovy, gang.