Correct - you create a Sling Servlet in Eclipse here  -- under the <packageName>.core.servlets: Then you deploy your project and the Sling Servlet is deployed as part of the OSGi bundle. Hope this helps.

You would need Target to perform this use case.

This is an older article - but sounds like what you want to do. Build content in AEM - ie a newsletter and use Campaign to mail it: Adobe Experience Manager Help | Integrating Adobe Experience Manager and Adobe Campaign Standard to create Newletters

What exactly are you looknig to do - you want to write a URL that points to an extenal site to a node property?

A Pathfield resource type is to open a path in the AEM JCR - when you click on a PathField - you will see something like:

Read through the links provided here - they explain everything you need to know for this use case.

When you say ROllout - are you referring to MSM?

Arun's response was correct in this situation. Nice answer!

Are you seeing any browser or log error messages?

Excellent response Arun!