1) a)  Since you have list ready, create a workflow step & map the tags accordingly.3) Use the validate & other methods available. Please referhttp://dev.day.com/docs/en/cq/current/widgets-api/index.html?class=CQ.tagging.TagInputField4)   Use a filter to fill the tree as per user login info.   Or se...

1,3,4 requires custom implementation. For depth how much tag you are planning? Challange would be authors to select those tag & activation will be slow. 

Out of the box provides it already. Attaching snapshot & more details look at /apps/geometrixx/components/topnav/topnav.jsp[img]TopNav.png[/img]

The tagging model does not imply any relationship between siblings. To  improve usability of tagging alphabetical sorting in the UI is provided.  We encourage you to attempt an application specific solution probably by overlaying [1].[1]/libs/cq/tagging/widgets/source/widgets/admin/TagAdmin.js/libs/...

WHat exactly you are trying to achieve? Refer [1] [1]http://helpx.adobe.com/experience-manager/using/creating-custom-aem-workflow-steps.html https://dev.day.com/docs/en/cq/current/workflows/wf-extending.html

Why don;t you use form component?   BTB what is the action you have specified and only work when you have submit action which is missing in your sample.

Are you starting AEM from double clicking or through start up script? Because location of sling.properties deponds on method you are starting.

For trial version check with sales team http://success.adobe.com/en/na/programs/rfi/dm_sales_inquiries.html

Did you tried setting acl permissions at plugin node level?

Might be Error status code is not set.  Check from the request tracer in felix console for post request what & all servlet are called. If everything is OOB one file a daycare ticket.