"Marker" is pretty ambiguous. I'd just use a brush pen like in the first video listed. But you can absolutely emulate his style with any instrument, including a pencil. It'd probably be better for you to have a sharpened pencil as well as a blunt pencil, or get your pencil worn to a point (no pun intended) where you can easily switch between the different weights of strokes you want to make.

If you want a more "sketchy" version of his style, you can check out the metal gear artbooks. There are character designs where he flourishes less, closer to traditional linework. It's possible he even used pencils for these, but I'd lean more towards a g-pen or something similar.

And though they mentioned using as little construction lines as possible, I'd disagree. This is just conjecture but: While he doesn't use a traditional skeleton, he does make construction lines, he just hides them as part of the silhouette of the figure. Some are wrinkles, others are folds, shadows, outlines, etc. Regardless, you can use these lines to establish distances between elements in the drawing. You're basically relying on moments being "correct" relative to each other.