I'm looking to add a header to the 2 pages we have with Category Blog pages. I want to add an RSS button to subscribe to these pages.
Any insight on how I can add this without hacking the core Joomla Files.
There are some really simple ways to do this.
Create a module position in your template file, then create a custom module with your RSS button and assign it to the module position but only on those pages. Using RegularLabs / NoNumber can make this incredibly simple.
Create a joomla override (not a core hack) of the category blog content and add your module directly into the category blog page layout. Then just create your custom module as a matching header. It will only ever show up here.
Add your RSS button to the category blog description (in the Content area) then set your category blog to show the description.