See pictures of my existing front door lock, I would like to replace it with Nest Yale. My questions are:

1) Do I need to buy anything else apart from Nest Yale?

2) The Nest Yale is smaller as compared to my existing lock, so I would have to paint the whole door again? from both inside and outside? how big job is this? DIY?

3) Nest Yale has only 1 latch, but my current lock has 2 latch. How will it work?

Would really appreciate your help !!