As someone that recently got back into digital art may I suggest switching inkscape for Krita? I prefer Krita as I found it easier to use, has better brushes, and great settings options for my tablet (if you eventually get around to using tablets)
Other than that I'd also suggest Libresprite for creating pixel art/animations. Godot for creating games (the tutorials online are fantastic and they even have focused tutorials for kids making games)
I'd also suggest an IDE like Neovim with Lazyvim or DOOM Emacs. either/or are invaluable learning tools for kids to get into development. PLUS the added bonus of teaching them VIM style navigation which many tools use and it'll make them feel like "uber haxors" cause it's really fun once you learn to navigate your machine purely with your keyboard.
Also if they want to get into web development I'd consider installing Astro as well. It's a fantastic and easy to understand framework for building sites that will allow them to build in a dev environment and then push their projects to "production" combine that with tailwind CSS and it's a solid base to get them going.
Also maybe even consider using a terminal emulator like Kitty or Wezterm. both are great and they can customize their terminals easily with like kitten-themes to make them unique to their machines. It's just something that's fun to play around with.