Well 5 colors for 16x is like the perfect amount of shading imo, but the 3 colors for the 32x one is so that I can practice things like shape and rendering different materials at a more basic level. The shading could just come natural afterwards, but limiting yourself to midtones, highlights, and shadows helps you better understand the textures and how lighting affects them. And I like the challenge I dunno it seems more interesting to work with limitations. It kind of creates a nice style imo.

Better than your original one but it needs to be more dynamic. The leaves clutters look more like balls than anything and the shading and colors can use some work. Quick edit.

How big are your pieces? If you want to print out an 11x17 inch paper then the quality of the print depends on the resolution you want to use (dpi).
Do you use Photoshop? If you want to print at 11x17 then you just need to have the ratio of your drawing be about the same as 11x17. Using the standard 72dpi resolution in Photoshop your drawing would have to be 792x1224 pixels, but then the quality of the print might not be super crispy clear.

Do something like this lol

Am I the only one who liked the original facial expression better? He just seems mildly surprised in the newest one lol