Dave Filoni, whose favorite Jedi is Plo Koon wanted to include a Kel Dorian youngling in this story arc, but George Lucas nixed it, feeling the little alien was too ugly.
The newsreel that opens the show features a rare flashback showing how Plo Koon first discovered Ahsoka Tano when she was very young. Plo Koon still wears a Clone armor gauntlet which he wouldn't have had at this earlier stage. Since they didn't have the budget to alter his forearms, they textured the armor to look like a cloth part of his robe.
After the release of Star Wars: Episode VII - The Force Awakens (2015), many fans speculated that Starkiller Base must have been converted from the Kyber crystal rich planet Ilum. This was finally confirmed by Lucasfilm in Pablo Hidalgo's 2019 reference book "Star Wars The Rise of Skywalker - The Visual Dictionary."
The planet Ilum was first seen on screen in Chapter 14 (2004) and was also featured in the 2011 video game Star Wars: The Old Republic (2011).
The crystal cave and the mechanic to place crystals to direct sunbeams and unfreeze doorways on the planet Ilum are a playable feature in the 2019 Jedi - Fallen Order videogame.