The same topic has been discussed here:How to maintain a track of users who have downloaded an asset?

Its not really clear what component you are referring to so its better to provide a specific use case so we understand the requirements. Meanwhile you can check the following document to get some idea on how to create/extend AEM components:Developing AEM Components 

You may want to check the following doc:Creating Page Templates

You may want ot check the following sample project and compare the structure with what you have and make sure Coral components have been used properly. Creating a Granite/Coral 6.3 Multifield HTL component for Adobe Experience Manager

Check the following documentation:Jackrabbit Oak – Authentication with the External Login Module

I have seen user synch in publish instances [1] as well as author to publish [2][1] User Synchronization[2] How to Replicate users and groups from author to publisher

I assume you meant "how we can increase the upload speed to DAM". You may find good suggestions in this post:What is Best way to upload assets in to AEM in Bulk? Also asset offloading:Assets Offloading Best Practices

Can you clarify if this WARN is causing any performance or functionality issue ? I am not aware of any existing workaround.

Hi, The referenced Jira is awaiting prioritization. So its not been closed or released.

Ref: AEM (AMS) will be able to connect Private AD (Active Directory) using LDAP Connection?The following document might be helpful to you:Configuring LDAP with AEM 6