Robby,
I don't hear Gord in your voice either, or Cat Stevens for that matter. And with Ian Anderson, I mostly think of his flute playing.
You have a nice singing voice and an interesting, unique sound. I find that many people sound quite different when they sing than you would expect from hearing them speak.
I don't sing (well, I do, but I shouldn't), but I do write, and there is always a concern that what we create will be derivative, or unconsciously plagiarized from other artists that we admire. Just the fact that you are concerned about this speaks well of your artistic integrity.
I would say, just keep on doing what you're doing