Well, funny story. Because people keep asking if they can put an i6 screen on their i6S. The general consensus is no. However your question is kind of the opposite. So you want to use the i6S screen? Which near as I can tell, doesn't have readily available parts. But, if it did. They did use some i6S parts, a digitizer/lcd, on an i6. And it didn't exactly work, from the pictures. This was pre-release. All that was shown, was the screen lit up, with a gear logo on it. So, would it work? Maybe. Would it do what you want? Not sure, if you could just get an i6 lcd/digitizer anyways?