I’m sorry about posting this here but these forums have way more surfers that Mixamo’s and I was hoping to get a quicker response here.
I currently don’t fully understand when they say that I’ll have access to the full character catalog and a limit of 50 animations per month.
Lets say that I pick a death animation and animate 50 different characters with it for a total of 50 animations. Is that all I can download that month and need to wait till next month? Or do I have 49 more animations that I can unlock and be able to apply them to any character and be able to download them too?
Thanks for reading me!
Feel free to post these types of questions on our Mixamo forums - we do monitor it and respond to all posts there. 
Animations are per character. If you animated “death” on 50 characters that would use 50 animations from your plan and you would need to wait until the next month.
However, animations can be regargetted within the engine, so I would never recommend putting an animation on 50 characters. That’s very inefficient! Instead, pick your main character that you want to work with say “male_01” character or something. Use him to get all of your animations (walk, run, shoot, die, etc.). Download all of the animations on that character into the engine. Now import your other characters into the engine. As long as they are using the same skeletal asset the animation will play on all of them. If it’s a different skeleton you can duplicate the animation and retarget it for your other skeleton.