I have fixed a lot of iPad minis and everyone here is right. You need to make sure those areas are taped, which it looks like you have. However, let me tell you a place to tape off that you might miss. I was working on an iPad mini once and long story short I couldnt get any digitizers to work with it. They all had ghost touching etc. I finally disconnected the digitizer for the 100th time and looked on the back of the connector that connects to the motherboard. There are what looks like 20 plus solder points. Make sure that this part has kapton tape or some type of tape on the bottom of it. If it does not, the back side will ground out on the inside of the iPad mini. There is usually an adhesive pad in this area from the factory, but it can get pulled off when removing the original broken digitizer.