When you purchase a painting, you own the physical artwork but not necessarily the copyright. The artist typically retains the copyright unless they transfer it to you in writing.
Ya, do it.
The copyright date on something is when it was CREATED or first published, and the copyright lasts for about a hundred years after the author's death, so YES, anything with valid copyright date of 2002 or 1993 are till in effect. On the other hand, it is a good question whether a famous painting still has its own copyright and whether a photograph or digitization of that famous painting may have its OWN copyright dates, as derivative works of the original.
The artist is concerned with protecting his or her copyright.
Almost certainly, yes. The copyright laws protect the image of cartoon characters. When you sell it for profit you are stealing the right of the character's author to sell his own work.
Looff's carvings are in the public domain, but if the painting was made later (between 1923 and the present), it would have its own copyright.
As long as the painting is entirely original, no.
Altering a copyrighted painting to teach a technique is still copyright infringement as that falls under derivative works.
If the painting is still protected by copyright, you would need a license to create a derivative work.
All art is subject to the copyright of the original artist anyway.
If you are not the composer of the song then you can NEVER take the copyright as yours; you would have to purchase it from the copyright owners. Also, when the copyright expires, 50 or more years after the author's death (or after publication, depending upon circumstances and national laws) it is no longer copyrighted at all and nobody can possibly own the copyright.
No you cannot "claim" copyright unless you are the original artist/author. Just because you "found" a copy of something does not mean you own the copyright for it. The only way to obtain copyright is to create it yourself, hire someone to create it for you, inherit it, or purchase the rights from the legal owner.
Each book has its own copyright information.