I'm interested and would like to talk to you about the requirements a little. I have Skype and I am perfectly capable of talking with voice, I also have Mumble and Teamspeak installed so whichever is your preference will be fine. (I don't have or use Discord though)
I'm a capable pixel artist but I'll be honest in saying that I generally prefer to work with slightly lower resolutions than the two images that you've linked to, or at least when I know that I'm going to be creating a number of animations for the sprite, just to keep things within a reasonable time frame and such, but that's something that I'd like to talk to you about, what is your desired or target sprite resolution for your character(s)?
Here's a quick sample that I have on hand of something that is closer to the Castlevania sample that you've linked a video of, I made this not too long ago for a small game jam entry with a steampunk theme:http://imgur.com/02DbAY7
I am capable of higher resolution sprites and this is an unfinished sample but let me know if you'd like to get in touch and talk about this a little and we can see if we can figure out if we'd like to move forward or not. No matter the outcome, I hope you find a good artist for your project!