VTK’s Qt C++ classes are not wrapped. The main reason is that, since they are Qt classes, they would have to be wrapped with sip (for pyqt) or shiboken (for pyside) in order for them to be usable with pyqt/pyside. But at the same time, they would have to be wrapped with vtk’s own wrappers for them to be usable with other VTK classes. In other words, it’s logistically very complicated to wrap QtVTK classes in a way that would make them usable.
So when VTK and Qt are used from Python, the connections between VTK and Qt must be done through python and not through C++. That’s why classes like QVTKRenderWindowInteractor and packages like qml-vtk-python exist.
It’s very interesting that QVTKRenderWindowInteractor gives the same GLEW error. Can you post a bug report at https://gitlab.kitware.com/vtk/vtk with some details?