Mixamo has now removed most of the models. I don't think you can download the player models that used to be on the website anymore (Erika Archer, Goblin, Knight, Paladin, Vampire, Warrior, etc.).
ALL ANIMATIONS ARE FREE FOR A LIMITED TIME
That's right. stop what you're doing.
There are 2,496 free animations on Mixamo.com
I suggest you all go to the store, search "pack", and download a bunch of packs of animations (will save you some time, grouped nicely, etc.).
Note: Don't worry what model you download the animations into.
Mecanim will retarget these to whatever humanoid you want just fine.
1) Once you've found a pack you want, click on it, choose a character, click "Add to my assets", "View/Download", then "Queue download".
After downloading each pack I went to the "My Assets", then "Animations" and deleted everything after each download, because it gets messy fast.
After clicking on "View/Download", you'll be asked about file format, pose, frame rate and keyframe reduction.
I'm not sure the best settings here, but there's a small guide HERE.