Chosen Solution
I did a repair on an iPad mini 3 and the customer said half of the screen was unresponsive. I have the ipad now, and it seems correct. The top half is not working whilst the bottom half is. Do I need just the digitizer or the LCD too?
If the glass is OK, just get the LCD replacement. iPad Mini 3 LTE LCD Replacement [linked product missing or disabled: IF277-004-1]
If the picture displays correctly, but half the touchscreen is unresponsive, then you would only need to replace the digitizer. You would only need the LCD if the picture is distorted or damaged, or on the iPad Mini 4, since the LCD and digitizer are one piece on that model.