Sorry, for the late response.
Blake, is the easiest character because of her quick movement and how spam able her Shadow-Strike is.
Ruby, on the other hand has potential to be just as fast as Blake. Ruby's Combat is not the best, but her skips is what keeps her on par with Blake.
I would say, Blake is the fastest character and the easiest to learn.
While Ruby is almost just as fast but has the most difficulty.

Also, I strongly recommend you check out the 'Guides' section! I've posted the skips, and how to do them there for every character, and every level!

Once again, I'm very sorry for the very late reply. Usually I'm always on top of this stuff.

You're more then welcome!
Feel free to add me on Steam if you have anymore questions, or need any help!
Steam: Available
Shouldn't have a profile picture, and should have 750 Hours+ On RWBY, to narrow it down if there is multiple.

Nice...
Just give your Steam, and I'll add you when I get the chance.