couple of quick things1. You are using log.debug. Have you enabled the configuration to log the debug level ?? else use log.info or log.error2. How have you created your session ?? 

As @scott mentioned you can use lots of menu components like JQuery, Bootstrap etc. and develop any type of menu

It should work. Refer [1] if it helps[1] https://docs.adobe.com/docs/en/cq/5-5/developing/components/edit_config.html

http://<host>:<port>/libs/granite/operations/content/diagnosis/tool.html/_granite_queryperformanceClick on 'Explain Query'. Add your query here and see the explanation. You also attach the same here

This is really helpful !! Thanks for sharing....

This is really helpful !! Thanks for sharing....

When you have @component annotation and override activate() method it should automatically initialize when bundle become 'Active' status. To make it immediately active when the bundle is deployed, use @Component(immediate=true)

Open a support ticket and see if they have any better solution !

Can you share your code snippet so we can see if something missing

to add to @jorg, you need to have a mapping between the data and your content modelling. Once you do this exercise, then it would be easy to come up with the strategy of doing the migration. It may be directly creating an xml structure and uploading it or it may be writing a simple service to create...