Currently I am attempting to do this project using components I already own. Upon scrounging through my parts I discovered a dozen stepper motors and matching controllers.

28BYJ-48 Stepper Motor and ULN2003

I am considering using these instead of much more expensive servos to control the neck functionality. If I use this setup, I may end up using a microcontroller as a small dedicated "servo neck controller" that directly interprets a standard servo signal from one of the pixy cameras.

Added:

After considering the options, I decided to go with a standard futaba servo, a 3003. The option of using a stepper was fine, however I would have had to tap into the accelerometer in order to find out where the stepper motors were. That or find another way to track their motion. Servo it is.