Creative writer for sci-fi horror project

I am having a media website developed (stage1), and the first part of that development is a project codenamed BDR. The project will include illustrated novel, comic(s), storyboard and card game. All items under the main project will be developed using the identical story/timeline. I have written the outline of the story without specific detail. It does have a start, stop feel to it at the moment. I would allow the writer to change/include, alter the story by up to 20%. I believe that personal creativity should not be withheld, and is a positive force to be welcomed.
However, the copyright has to remain 100% mine without question, so if you don’t agree to this, please don’t bid. You will be credited with story development.
Story outline:
It would be about 500 years into the future, and be set on the moon Titan (moon around Saturn). A science team working there gets infected with a DIGITAL nano-bacteria. As coms go down the soldiers are sent in to discover what’s happened. The infection spread via tissue and electronics. Everything starts to crumble.

Please give a fixed fee for the storyline, then If any, the subprojects under that, i.e.:
Comic book development £?