It is likely to be as you say ...
Are not aware if at some point they changed the iPhone screen? The touch id?
Since that error is practically on the iphone 6 hardware because you changed an id and an broken touch the cable connects to the LCD screen.
See if the USB cable, this fine home button. If iTunes is updated look and try restoring denuevo, if you can prove in a better pc.
But the best thing is that you take it to Apple for service if you still have warranty or else ask how much they charge.