[sgreco]

You definitely don't need a CNC to make a swerve drive, if it's going to be coaxial and you're going to use bevel gears, you probably want to find a shop to help you out. My team made a full swerve on a manual Bridgeport mill in 08.
We used a 4-axis CNC this year, but you certainly don't need that to make it good.

For sensors, my team finds hall effect sensors to be the best because they are absolute sensors which saves time centering the modules(the reading is usually more accurate for us than we found with pots and encoders).

Although you are only allowed 4 CIMs, you probably wouldn't want it for steering anyway. They are too fast. I would use the globe motors. My team used the Denso motors and they worked fine as well.

If you have any questions feel free to PM and I can answer any questions you want about mechanical aspects of swerve.