FAA Regulation

No more than three as long as the Remote PIC maintains visual line of sight. As many as he/she can handle. No more than one. 

Denial of application for Remote Pilot, waivers, or suspension/revocation, or a civil penalty.  Jail time of up to 1 year A required checkride with the FAA

600 feet AGL. 500 feet AGL. 400 feet AGL.

The FAA Inspector-in-Charge. The lead visual observer. The Remote Pilot in Command.

Compliant with Part 107. Part 107 does not apply to this scenario. Not compliant with Part 107. 

No Medical Certificates are required. A Class 3 Medical Certificate A Class 2 Medical Certificate.

the Remote PIC.  the controlling agency. Air Traffic Control.

12 hours. 8 hours. 24 hours.

Quadcopter capturing aerial imagery for crop monitoring. UAS used for motion picture filming. Model aircraft for hobby use. 

Remote Pilot in Command. Commercial Balloon pilot. Designated Pilot Examiner.