Answer 1

This is probably more a matter of personal preference but I would recommend pyqt.

Its important to note that QT itself is a framework for c++ and pyqt is the python bindings to that framework. The advantage is that you can easily prototype apps using python and rewrite them in c++.

Another big advantage is the qt designer which is like a wysiwyg editor for rapidly prototyping the ui (though its output python code can be messy). I dont know if there is any good equivalent for tkinter.

One thing pyqt does lack in my opinion is good documentation. When searching for example code or information you'll find most of it is for c++ and not python. So knowing some c++ does help a lot when using pyqt.

Personally I use pyqt to create pipeline tools for 3d rendering software like Nuke, Maya and Deadline which all use modified versions of the base qt library for their ui.