[Fixed]-Is there a way to have custom content with mezzanie/Django

See the docs on creating custom content types. The primary approach is to subclass the Page model and add your custom fields.

Alternatively, if your custom content is conceptually independent from your pages, it might make sense to create independent models with relational fields to the RichTextPage model and edit them through inlines.

Note that the mezzanine docs on custom content types and the django docs on inlines use the same author/book example so you can easily compare the two strategies.