as there are monetary penalties for misuse, you should check with MS rather than a user forum.
In general the developers license is free to use for testing and development. You don't need a Visual Studio license. The main restriction is it can not be used to collect or process production data.
A production environment is defined as an environment that is accessed by end-users of an application (such as an Internet website) and that is used for more than gathering feedback or acceptance testing of that application.
while you can load production data (generally not a good idea if it contains PMI data), this can only be used for testing, not for instance, to produce a report that is used outside of testing.