Try taking the battery out and holding the power button down for 20 seconds or so and then try to turn it back on. Have you tried to power it on without the battery in but plugged into the charger?
Possibly the vibration motor is bad. You can get the part for a couple of dollars. Do you know how to replace it? If not contact me because this is what I do, I can do it for you.
When the touch ID stops picking up touch and the home button still functions, that means the touch ID will never work again. The touch ID senor that came with the phone itself is the only one that is compatible with that iPhone. The best thing to try would be find a broken iPhone 6 on eBay and see about getting just the home button. Maybe a OEM Apple button will work.
