>I thought white on white was common on colored pics, but now that I looked into it it's way more common to actually shift the hue and saturation.
Yep, though it really depends on how much you're relying on lines to seperate subjects, I don't know if you did it consciously or not, but here, >>2276
your line work is subtle enough that it's not going to delineate the hair from the skin. I really can't think of any character off the top of the head that is pure white hair on pure white skin (outside of manga, but they use screentone there), and even if there was, the artist would have to use heavy linework to keep the areas separate.
I supposed I should also say you're not limited to "gray" as far the the slight tone on the hair. For example, the second image you posted looks like it's mixing a very subtle amount of blue/green into the hair, just be aware when you start adding shit like that you can very easily fuck it up, adding too much color and then veering hard into anime style territory. Now it's up to you whether or not that's a good thing, just be aware it will have that effect if you use too much color in the hair.
>Isn't that the left?
If I wanted to specify from the character's perspective I would say "proper left", by default I also talk in terms relative to the viewer unless otherwise specified. I don't know about other artists on this board, but for me as an artist viewing work, I am always mapping my explanations from viewers perspective. If you wanted to be pedantic, I could say "viewer's right arm", but I'm lazy. This is a problem associated with human subjects.