Valid to the Beholder.

Question: Are other interpretations of metaphor valid?

I do not think that the author's intended meaning of a metaphor is the only valid interpretation. I do think that there is only one interpretation of the metaphor that correlates exactly with author's intent. However, I do not think that this is the most important use of a metaphor. I think that any interpretation of a metaphor is valid to the person who interprets it. If someone can see a connection between Richard being a lion and Richard being a transcendent triangular square orbiting the Triangulum galaxy, then it is valid to that person. That does not mean that any other person has to agree that this specific interpretation is relative at all to them. I do not think that metaphors are meant to be contained to the intend of the author. It may very well be that the author never intended for you to get anything else, but maybe the connection that the author made, helped you to make a connection that otherwise you would not have made. Metaphor meaning can change and be applied differently to different people and scenarios, I think.