I have selected the STM32F030F4P6 as the microcontroller for this project. My main search criteria were ARM M0 based, at least one I2C peripheral, ADC with at least 4 channels, availability, and price.

The STM32F030F4P6 fit all the criteria and the price is right. I ruled out the Cypress parts for not having enough IO. Between the Zilog part and the two ST parts, I would rather use ST since I have experience with them. Between the two ST parts, I chose the one with a larger available quantity.