Buck Boost Design

I would like to know whether the design given below can be used to for a Buck Boost that has input range from 10.8-16.8V and Output 12V. Output current is 0.5A.
This is the application circuit that I got from datasheet of MP28167GQ-A-Z.

Could you please clear a few more questions regarding the design?

  1. I would like to know the equation for calculating the inductor value for Buck Boost converter.
  2. Could you please specify the VIH and VIL for the Enable pin?
  3. Is the ALT (Alert) pin open drain? If not so then what would be the voltage in that pin?
  4. Is I2C mandatory for this design?
  5. If I2C is not used in the design, the is it in PFM of PWM mode?