When it comes to L, I would go for off black. It usually look better on people then jet black. It kind of depends on your skin tone as well. Like, I'm SUPER pale, and pure black makes me look like a ghost, so I don't use it.
For Near, I would go with white, his hairs doesnt look like it has silver at all in it to me. Pure White. But, I think white in scruffy is sold out?
Ah, for my Mello cosplay I got Maxine in butterscotch blonde.
Now, butterscoth is perfect for Mello, the color looks great.
But, what they don't tell you about Maxine, is it's shorter in the back then the front. The front goes about to your shoulders, while the back is about the nape of your neck.
All I had to do was cut it though, and even out. I think it's perfect if you aren't afraid of cutting wigs. After I cut it, it was about to below my chin. Its a little short if youre following the anime and not the manga, but you can make it as long as you wish. I also made the bangs thicker by cutting in more.
I have pictures of it if you look on my page.