Unless other arrangements were made, rights would have passed to his children.
Walli Woo Entertainment and Winding Brook Way Music control the songs. The screenplays, movies, and Broadway show each have their own additional rightsholders; for example, the stage adaptation of the screenplay is copyright Thomas Meehan and Mark O'Donnell, New Line Cinema holds the rights for the new movie, Stage Stars Records holds master rights for the soundtrack...
I would assume Richard O'Brien still holds the copyright.
Unless other arrangements were made, the creator is the initial copyright holder.
Warner-Tamerlane.
Muppets, Inc.
Unless other arrangements were made, the creator is the initial copyright holder.
The Richmond Organization.
The Rank Organization.
Catchme.com is registered to Slingshot Labs.
Little, Brown.
Yes, altering an image does not automatically remove its copyright. The original creator still holds the copyright to the altered image.
Unless the job is work for hire or work for employer the photographer holds the copyright.