SSDT: Requires Visual Studio? Requires connection to SQL Server? (SQL Server 2016)
Yes you can work offline but it will be difficult to develop and test without the input/output connections files/tables your package will use. 

One option is to install SQL Server on your pc, create a database and copy the source and target tables and some test data to your pc. Then you can develop and test locally.

Deployment will be difficult unless you have ssdt on the server. Otherwise you will need access to deploy to the server from another machine.