Cross-art copyright

Question

I have a basic, non-lawyer-level, understanding of copyright, trademarks, and patents (US/EU).

I have the following question: how is cross-art copyright regulated? What I mean by that is inspired by progamme music. Here is the process:

• There exists the copyrighted artwork A in artform F1;
• You create a new artwork B in artform F2, whereby not only B is "inspired by" A, but it "tells the same story".

There are obvious examples where B is a copyright infringement. For example if A is "Star Wars" by F1 being "Film", B being a written novel describing the same story with the same characters.

However, it gets fuzzy when the derived art is in an artform, where the storytelling is not obvious, or even subjective. When somebody creates programme music, based on "Star Wars" (not deriving from any of the movie's music material), or creates a painting series describing events from the films (avoiding trademarked material, think for example abstract paintings).

What are the copyright-regulatory frameworks and restrictions of such works? Let's take the following, more concrete example:

• There is a novel, "Harry Potter and the Prisoner of Azkaban", which includes 22 numbered chapters, each with its own title (see here)
• There is a programme music set created, containing 22 pieces of programme music (not related to any musical material of the Harry Potter films)
• There is a painting series created, containing 22 pieces of paintings

The questions are:

• Are you allowed to use the chapter titles for the titles of your work? (programme music, paintings)
• Are you allowed to use characters (in the paintings) or character names (for titles)? (Yes, I know, this gets complicated by copyrighted characters.)

How does copyright law handle such cross-artform derivations?

For trademarks, my basic understanding gives me some rules to go by, but I'm totally at loss for the same for copyright. My basic instinct is going into the direction of fan-art (fanfiction and such), which is already a swampy territory, but this seems to be one step removed even from that.