Go to useradmin, For everyone group make sure you have read permissions to /etc/tags and folder under it.In AEM 6.4, the path for the tags would be /content/cq:tags. You can check for the same permission for the everyone group.

my 2 cents : I understand what you are trying to do here but don't think it is possible OOTB. IMO concept of  CF relies on the content structure which inturn relies on the referenced content(asset, text etc.) which later can be consumed internally or externally where all these assets reside at a cen...

Try hitting the instance with direct host port (http://HOST:PORT/<CONTENT_PATH>.html) and see if anonymous users can access the page or not

AEM (only author instances) with MongoDB only supports replica-set architecture. Sharding is not supported.(1) : Recommended Deployments

302 status code would suggest an issue on the apache level or resource mapping configuration. Can you bypass the webserver and directly try hitting the author/publish instance

You need to modify your index definition(say DamAssetLucene) to include an analyzer which would have a file which contains the stopwords. You can add all the metadata keywords in this file and after you reindex, fire the query you won't be able to query for such excluded keywords.More information on...

you can rely on prefetch section at (1) for prefetch of dispatcher cache(1) - Optimizing the Dispatcher cache

Moving pages which were already publishes would trigger a DELETE request for the publish instance, move the page to the new location in the author instance and then replicate it back to the Publish instance.You can do this operation by either disabling the replication agent for a while so that items...

You can use the content fragment models by installing a feature pack and expose assets to the public and consume it in external apps and SPAs. In 6.4, this is an OOTB feature(1) : Content Fragment Models

No it's not a bug. If you add/upload an image to the assets console, it would refresh to show the current state of the folder with new files added