What's the difference in meaning between "usual [someone]" and "classic [someone]"?

What does "like" mean here?

"Like" in this context, means to be similar or have something in common. Dumbledore tells Tom that he is similar to Tom being that he can do magic too. Ex: My sisters look like me. Ex: I am like my mom; very stubborn. Ex: That cat looks like mine!

Can I replace 'on' with 'of' instead?

No, you can't use "of". but in some cases like this one, you can use "about" instead. Saying "This was considered the very best source of information about the animal" would also be correct. Ex: What's your opinion on global warming? Ex: I guess we don't agree on this.

Is "kick to the curb" an idiom? What does it mean?

Yes you are correct. "Kick for the curb" is an idiom meaning to discard, abandon, or dismiss someone or something that has become redundant, obsolete, useless, or unwanted. Ex: I can't believe that after 20 years the company would just kick me to the curb like that! Ex: I think it's about time we kick this old computer to the curb. Ex: I heard Jenny kicked her boyfriend to the curb last night. They must have had an awful fight!

What's the difference in meaning between "usual [someone]" and "classic [someone]"?

Good question! "Classic [someone]" means that this person/group is doing something they're well known for, whether it be notoriously good or bad. "Usual [someone]" means that they're being themselves or acting like themselves. It's not something that's specifically good or bad or what they're well known for. It's just the norm or standard of them. Ex: Classic Stanley, always being so kind and encouraging to strangers. Ex: Oh, that's the usual Jim, always talking to himself while working. Pay it no attention.

What does "Classic" mean here?

The word "classic" here is used to emphasize that something is typical or usual. In the video, he says "classic" to make fun of Liv for having homework that is five years late, as if it is something that she would normally do. Here's some more examples of this usage of "classic": Ex: You forgot your keys? Classic. Ex: A: John will be late to the meeting. B: Classic John, always running late.