Hi
You need to place your customised 'site-finder.get.html.ftl' file under the 'web-extension' directory so that it overrides the original Alfresco file. So, the path should be:
src\main\resources\alfresco\web-extension\site-webscripts\org\alfresco\components\site-finder
Use the 'src\main\resources\alfresco\site-webscripts' directory for your own files - stuff that is not overriding Alfresco code.
The path for the customised 'site-finder.js' looks correct, try refreshing your browser cache.
Dan