Yes. In most cases the copyright is held by the author/artist, the publisher, or the originating newspaper (depending on the terms of the creators contract).
Gloomy Sunday will be protected through 2038; it is controlled by Warner-Chappell and Carlin America.
Without permission, and assuming it doesn't fall under the "fair use" exception, it would be an infringement of the artists/writers copyright
few of it is available at comic-skulled.co.cc .. I read them there
The copyright lasped on the death of David Selznick, but later it was renewed in the USA. It will remain under copyright there until 2045.
Drugs and other pharmaceuticals are protected under the patent laws not under the copyright laws.
Trademark yes copyright no.
Yes. All aspects of the film are still under copyright.
You need permission from the copyright holder or an exemption in the law.
A website is considered a "literary work" under copyright law.
Yes, if you have a copyright in any country covered under a multi-lateral treaty, such as the USA under the Berne Convention, your copyright must be honored and protected by the laws of the other 160 countries under that Convention.
Not particularly strict; it's under the same copyright laws as anything else.
If it is no longer protected by copyright, there are no rights to obtain.