Question: Does anyone know if the house number is included in Mapbox’ vector tiles, and if so how to access it for styling?

Answer: 
Version 5 of the Mapbox Streets vector tiles includes the house number in a new layer.

I used the following to add them to the starting style:

```
#housenum_label {
  text-name: '[house_num]';
  text-face-name: @sans;
  text-fill: darken(#cde, 20%);
  text-size: 9;
}

```
As far as I know, house numbers are not currently included in MapBox's vector tiles.

If you need to render a small region, you can get them in GeoJSON with [Overpass Turbo](http://overpass-turbo.eu/s/3mZ) (press "Run", then "Export" and "geoJSON"), which you can use in TileMill as a layer. For bigger regions you might need to process [planet extracts](http://download.geofabrik.de/) or the planet file itself.