The first quote is saying that each person has inherent value. You do not need to accomplish something incredible or prove that you are more clever than another person before you will be a worthwhile human being.
The second quote means to work to the best of your abilities. It is saying that the best of your abilities may not be the perfect way to do ...
"Animated" literally means "full of life or excitement; lively", but is also used to describe a process of making cartoons and the like, whereby inanimate things - for example, drawings, clay models etc - are given the appearance of moving, or being alive.
"Madness" can mean crazy behaviour, or perhaps wild, chaotic activity.
"Animated madness" therefore ...
"Get someone into something" can have several meanings, depending on the context.
In this case, an accurate reading might be "make sure that she starts rehabilitation." This could be a program or it could be a literal center. You're right that "get her into rehab" makes it sound like they might be referring to an actual rehabilitation center with a building ...
Is it an erroneous phrase?
It's not common, that's for sure. I would say it's erroneous in that it's missing the word "get", or "become": "they felt themselves get quieter". But even then, that would leave a native speaker thinking about your choice of words rather than what you're saying.
when can one say "I feel myself" or "They feel themselves"?
It is not a standard expression, but given the context is probably a joke euphamism for "masturbation". "Jack off" is a slang for masturbation. The expression plays on the title of the children's story "Jack and the Beanstalk"
It's a funny way of saying masturbate, without sounding too dirty or serious.
There is a difference.
This is a demonstrative pronoun. So, using it you, you specify which cat is yours. For example:
-There are many cats in this room. Which one is yours?
-Oh, this is my cat. (pointing at the cat)
But if you enter a room holding your cat, you might say to your guest, "Here is my cat." It sounds like you are introducing it to ...
This is a reasonably common idiomatic expression.
You are saying that the person is well established, and might be dominant in their field.
It says that "If you are not dominiant, then you are well estabished." But since being dominant is stronger than being well established it is also true that if you are dominant then you are also well established. So ...
If you say
A is ten times the wizard B is
you are essentially saying A is 10 times better than B in wizardry. In this context, Weasley is telling Harry that Cresswell is 10 times better than him [i.e., Harry].
I don't know the specifics, but it could mean that Cresswell's knowledge of wizardry, mastery over spells, and strength are all better than ...