I turns out that there are two I2C ports on the Edison but only one is currently configured for operation in the Edison Arduino IDE, I2C6 on A4/A5 or jumper J17-7/J17-9 on the mini breakout board. The other, I2C1 is on digital SDA/SCL on the Arduino Breakout board (J17-8/J18-6 on the mini breakout board) and without a software change to allow more than one I2C port will not work. Fortunately, this software change is straightforward to implement so both are practically available.
Now, how does one change the pullup resistance on the GPIO pins and the SDA/SCL ports?