Could one separate the LED Sceen from the Digitizer (Touch Panel)?

The short answer to this is going to be no. The screen is fused to the glass.

The long and difficult answer is yes. You can, but you need to work on several of these because the touch layer is bonded to the LCD and doing it wrong kills the touchscreen. You also need to have something to remove the glass from the phone and know how to clean it without screwing up the touch map on the screen. If you screw it up you might as well throw the screen out.

After you clean it up, then you have to apply UV glue and align the screen correctly. After that you have to cure the glue to the glass. After doing ALL OF THAT is when you can put it back on the phone.

You are better off buying a new screen assembly and being done with it.