Allegedly, his longtime assistant "Gwen" was given the rights. See the forum posting by his grandson Willy linked below.
The copyright for Alec Stern's work is most likely held by Alec Stern himself, unless he has transferred it to someone else through a formal agreement. The copyright automatically belongs to the creator of the work unless it is specifically assigned or licensed to someone else.
You would have to have the permission of the artist or company that holds the copyright on the artwork.
I would assume Richard O'Brien still holds the copyright.
The source of the lyrics, the album sleeve notes, or the artist's website will indicate who holds the copyright. It will be listed close to the © symbol. It will usually be the artist's record company.
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.
Catchme.com is registered to Slingshot Labs.
Little, Brown.
The Richmond Organization.
The Rank Organization.
Unless the job is work for hire or work for employer the photographer holds the copyright.