People say to dig down 6 blocks and have 6 doors on ground level. Does it have to be exactly 6? Can it be more or less?  Is that from the bottom of the door to the block the villagers feet is under? ![enter image description here](https://i.sstatic.net/n8TNf.jpg)
Also is there anything wrong that would prevent villagers from reproducing in this picture?
[![][1]][1]
[![][2]][2]
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  [1]: https://i.sstatic.net/YglqI.jpg
  [2]: https://i.sstatic.net/qq2ct.jpg
  [3]: https://i.sstatic.net/Whudn.png