That's true. I'd love to try that as we get to the end :) 
For Yugi's character design, I'd prefer 'Bonds Beyond Time' or 'Dark Side of Dimensions'. Since he looks more of a seventeen year-old :) Same for Jaden in BBT :) 

Now for Shadow, in her evil state, she would be using her whispers of persuasion on everyone in the school to bring out their shadow-selves, or the dark sides of their personalities, kind of like the ghost of Kaiba back in the first series :) If she couldn't have human friends that can see her, she would make those "friends" out of everyone's shadows. 

Here's a special treat; skip to 1:00

[youtube]https://m.youtube.com/watch?v=O_P-l3zOORg[/youtube]