Well, now I've revealed my secret identity! Oh well!
There is much more to Than Kosis in the rest of the feature. I've spent quite a bit of work on him, with always more room for improvement, of course. I have tried to keep him very "Burroughs" even as I have made him more than what he is in the novel.
Hagoja has been fun to write, with four characters to draw from. She's a combo of Lorquas Ptomel, Sarkoja, Tal Hajus and Dak Kova from the novel. I like that she is the one who personally ruined Tars Tarkas' family, and now they are virtually co-leaders of the Tharks. Things get much more interesting in the feature with that subplot as well.
Someone suggested I add in a love interest for Sola and it has really helped to draw out the themes of her family's past and the Thark cultural/emotional struggles as well.
The Woola material is nearly untouched from what Burroughs wrote, and it works nicely to give John Carter some emotional connection with Barsoom from the start, even if it's just a guard dog.

They look out for each other, essentially.
Yeah, I kinda gave Kantos Kan a huge promotion, from Dwar to Jedwar, but I wanted him to be an important character from early in the script and to be close to Dejah Thoris. It seemed like a good way to help show the Heliumites in their own environment before Dejah Thoris was captured and encountered the Earthman.
I'm glad you're enjoying the script! If the Pixar/Disney production succeeds, and it becomes obvious that there's nothing left for me to do with my adaptation, I'll post the whole thing. I'll try to do that before the movie is released, then us ERB fans can have some REALLY interesting discussions about the film! (And who knows if Andrew Stanton and co. might read my "Princess" script after the legal concerns have blown over and consider hiring me for "Gods"?!)
Let me know of any other questions or suggestions you might have about the script!