Hey Scott,
You can add a favicon to a Page Builder template by editing the Header HTML in the Settings tab of that template. You’ll need to make sure that their favicon image is hosted online and accessible publicly.
Navigate to the the Settings tab for your Template or Single Page, then click Header HTML.
Add the following HTML snippet to the top of the Header HTML contents. You’ll need to update the type based on the image you are using.
If the image is a png:
<link rel="shortcut icon" type="image/png" href="YOUR_FAVICON_URL.png"/>
If the image is an ico:
<link rel="shortcut icon" type="image/ico" href="YOUR_FAVICON_URL.ico"/>