Why? I believe there's at least three ways to turn your phone off right now, why do you need another one? As far as the magnifier, why don't you just set it for triple tap to use the magnifier?
The screen can be turned off with two screen tap gestures or quickly pressing the power button once. Placing a button in the quick panel would make the procedure redundant. Using those two methods alone can wake, or turn off the screen.
As far as magnification, go to settings/Accessibility/Vision enhancements/Magnification and go from there to create shortcuts or gestures to have the function the way that feels best for functionality. Clicking on Magnification type will offer different choices if that is toggled on for use.
