You have to remember that SQL Server Database Tools (SSDT) is an overloaded term within Visual Studio & SQL Server. There are actually two distinct tool sets that define SSDT. There is SSDT which is used to create database projects as a means for getting your database into source control and coordinating and automating builds with your application code using msbuild and associated tooling. Then, there's SSDT which includes the software for Integration Services and Reporting Services (SSIS & SSRS). That's for creating data migration and reporting projects, completely distinct from the other SSDT. It's two different sets of installs for the two different tool sets & everything.

As far as licensing goes, to my knowledge, all these tools are freely available, depending on what licenses you have. If you have a Visual Studio license, you can get the database project version of SSDT. If you have a SQL Server license, you can get the SSIS/SSRS version of SSDT. What ever cross over these two might have, I'm not sure.

SSIS won't do anything to migrate AdventureWorks to Microsoft Azure SQL Database that you couldn't do yourself by running the deployment evaluations with SSDT (the project, isn't this fun?) and fixing the issues. You could also just get the Azure version of Adventureworks. You can also play with the Red Gate hosted version of Adventureworks if you want[/url].