static landing page leading to author specific pages w/ “live” content

As i see your code in header.php and index.php looking messy (because of many if conditions).
If i’m understanding your problem then i do it like this

1. create separate author.php for both authors their name like author-cait.php and author-shannons.php
2. Give link like http://www.yousite.com/author/cait/ to button on static landing page.When user click on this,it takes him to author’s specific author.php if exist
3. create custom header.php for both authors name like header-cait.php and header-shannons.php
4. create custom sidebar.php for both authors name like sidebar-cait.php
   and sidebar-shannons.php
5. complete your code in author specific author.php for example author-cait.php contain only cait’s conditon,header and sidebar.

It makes your code looking beatiful,manageable, save from overloding of if conditions.