Nice studies man! The Junjito one is especially creepy (as it should)
As manner of feedback, I'd recommend to pay closer attention to the line weight use there. For example, in the Nayirix reference you can see the gir's hair and the character on the back have a distinctly finer oultine than the main character in the front, especially his Axe. And even with just lineart you should be able to, for example, have the character in the back have less weight overall. Otherwise the complexity make it hard to appreciate the layers of distance.
Here's a rough example using your same piece, just adjusting some outlines and tones a bit