Show only certain areas in the 'edit post screen'

Is there a way that I can only show certain areas on the edit post screen?

I am working on a site where users will only have access to certain areas of the post(s) created for them (I’ll be writing it, then putting it under their user name).

The idea is that they will be able to have access to plugins which show up on the post edit page, as well as the custom fields but nothing else (they won’t even be using the title or main edit area.

Also, is there a way to allow users to only edit what is created on their username, and not create new ones?

Thanks.