The white is Lyra Rembrandt. Different colors and different brands have different opacity. On the black paper it is very important that the pencils be as opaque as possible or they won't show up. Most of my black-paper work is done with Prismacolors, but the white from that brand is rather translucent, so the oil-binder Lyras work better.
I wish i could give you advanced critique, but I'd like to say somehow you captured the exact look of my cat, same look in the eye, same colour, same 'attitude', it's just remarkable. I always admire people who can draw - I can't, i'm a musician, not a visual arts person. But i definitely know when something triggers a reaction in me with art. You're so lucky you can do this!