Is it possible for art to have no meaning at all? That the purpose of the work is the physical for that's presented (lines, shapes, color, mass, etc).
OR Is it possible for art to have ONLY meaning and no physical form? i.e. can an idea be enough to be considered art?
I believe that you are on the right track. I also believe that too much time is spent searching for the "meaning" or the "message" in works of art. The matter was pretty much resolved for me when I read a great and underrated book by Tolstoy titled What Is Art? It is hard to find but not impossible. Since reading it I have never since been troubled by such questions as "What is the meaning?" of this story or novel or painting or other work of art. Below is the most pertinent extract from Tolstoy's book:
To evoke in oneself a feeling one has once experienced, and having evoked it in oneself, then, by means of movements, lines, colors, sounds, or forms expressed in words, so to transmit that feeling that others may experience the same feeling--that is the activity of art.
Art is a human activity consisting in this, that one man consciously, by means of certain external signs, hands on to others feelings he has lived through, and that other people are infected by these feelings and also experience them.
What Tolstoy concluded after years of thinking and reading about art was that all real art is the communication of feelings by one means or another. The artist must have a feeling to communicate in the first place. Tolstoy contended that a great deal of what is represented as art is really counterfeit art, because the artist does not have a genuine feeling to communicate but has some other motive, usually a money motive. And Tolstoy identifies the various ways in which people produce counterfeit art.
Tolstoy probably wasn't 100% right in his ideas, but no one is. The book is full of valuable insights. I highly recommend it. If you can't buy it, you should be able to find it at any good library.
I don't personally believe that a mere "idea" can be enough to be considered a work of art, but it can be a good idea in itself, or it can be a starting point for a work of art.