Per wiki policy, Spoilers Off applies to Fridge pages. You Have Been Warned!

Fridge Brilliance:

The fact that the Classical and Rock Tribes have crossed over each other's music several times throughout the show is really understandable when you consider that their genres are the most reliant ones on music theory, and thus they usually work well with each other. Musical groups of both genres rely on a format of sections, sharing the stringed and percussion ones most of the time. It also helps that some Rock and Metal artists have integrated Classical instruments into their style.
Having DJ Suki officially written out in "Troll Exchange Program" by sending her off to live with the Techno Trolls was the greatest way to do so. After all, how does an electronic sound like Techno music happen? By hitting buttons, sliding scales, and remixing the sounds and music on a computer or machine to make a new kind of beat, which is EXACTLY what a DJ like Suki would be perfectly used to! She may have been born and raised as a Pop Troll, but she's been utilizing and honing Techno Troll skills her whole life!

The concept of the Multiverse is explored further more here with alternate versions of characters appearing such as Pushy Poppy. Since we know that a Jerkass Poppy is a possible thing, what's stopping the appearance of far more villainous versions of Poppy or any of our characters? Like for say, a version of Poppy that wants to use the Strings to rule all Trollkind.
- And also worlds where any of the Trolls' previous foes won. Like say, Barb turning every Troll into Rock Zombies and succeeding in world domination.