OK, so I'd like to start off by saying I remember the book series and enjoyed it alot
You did a pretty decent job of making the first book into a screenplay, I was left wanting to see what you'd do with the rest of the series! I hope you do continue writing the rest of the series, the hints about Ax, Marco's mom, Tobias, Elfangor were all there and I really do want to see what you do with it!
I do think you should work on the stage directions a bit more, reading stuff like "anytime they talk it's telepathic, deal with it" was a little irritating (might be just me, but that's what my comments are), maybe instead describe what telepathic speaking might be like for the person watching it.
Also want to say, don't be afraid to add original elements because so far what you've added in has been great and I would love to see even more things added into it, maybe take something people will expect and turn it into something else?
Hope you find these comments helpful and hope to read more of your scripts sometime
(for the record, I was perfectly willing to ignore the Uranus fact)