In the FAQ we answer any questions you have around the Windward Engine.
All need to be licensed. If you have many environments then perhaps paying per report may be best for your deployment.
The RESTful Engine lets you generate documents from an application using a programming language other than Java or the .NET family of languages. To access the RESTful Engine, you make a Web Service call from your application. With the RESTful Engine, the document generation is not married to the application. The application makes a call to the RESTful Engine server and the RESTful Engine returns the desired output.
Java and .NET Engines are licensed per server and the number of cores running on each instance of the application server.