I populated the rest of the shield, and its seems to work — at least it shows up on the I2C bus. Further testing will require writing a library for it.

I also fixed the schematic view, so that it can actually be understood. This is something I like about Fritzing — you can do the schematic later.

While making the schematic, I also discovered that the version of PCB I have misses one connection (for the I2C address selection resistors), so I will need to bodge that in the prototype. The final version has that fixed.