When multiple sound engineers are working on a same UE4 project, each engineer's installation path differs. And the installation path is set from the Unreal project's DefaultEngine.ini. For many reasons, DefaultEngine.ini is governed by a source control system, like Perforce for example. So we have a problem that we can't set the WwiseWindowsInstallationPath with any specific directory and every time sound engineers run the UE4Editor, they have to set it as their own installation path.
For now, we marked the DefaultEngine.ini as writable file in our source control system. This reduces number of times a sound engineers should change the installation path but it makes other problems such as that the ini file is not sync'ed properly because the file has been changed locally and not resolved conflicting lines.
So, could you change the way UE4 initializes the installation path from DefaultEngine.ini to different one? For example, make the plugin reads the installation path from an environment variable and wwise installation process sets the variable proeperly and the variable can be set or changed from Wwise.exe.