Let me answer questions 1 and 2 for you.
1) The Tobii EyeX Controller eye tracker can track the user’s eye gaze on screen sizes up to 27″ when the eye tracker is mounted centrally on the screen plane, and the user’s eyes are at about an arm’s length distance from the eye tracker. The precision and accuracy of the eye-gaze tracking drops notably outside this screen size. The Tobii EyeX Engine runtime, that handles the screen setup and user calibration, currently only works for the eye tracker to be used with one monitor at the time.
2) There is no EyeX SDK for Python.
For the third question, I’ve seen some program or another like that mentioned around the forum. Try search the forum for it (search box on the main forum page).