Local files cannot be monitored due to security restrictions in web extensions, enforced by Firefox.

In your case, I guess .tpl and .php files are used to render a page that's served on http://localhost? Can you use localhost URLs to set up a reload rule?

Note that in Live Reload, a Host can monitor itself. Example:
Host URL: http://localhost/some/path/*
Source file URLs: http://localhost/some/path/*