The shooter has no verbal communication with the pilot at all. Shooter is on the flight deck circuit, and pilot is communicating with the tower. The only time I communicate with the pilot is when I return his/her salute indicating they are ready to go flying. At night, the pilot will turn on the a/c anti-smack and position lights indicating they are ready to fly. If they don't want to go flying, the pilots look at me and shake their head "no." At night, they won't turn on the a/c lights or they will turn them off. If the pilot wants to suspend, they call it out on the tower circuit, and the tower can suspend the launch with a button.
Before I press, or direct the pressing of the fire button, I double check a whole bunch of things (in a nutshell):
1. aicraft properly attached to the catapult and the correct holdback bar is on there.
2. I have authorization via a green beacon light to start launching.
3. the catapult is properly "stepped up" and is mechanically ready to launch
4. the front end is clear to shoot
5. the pilot is ready to go flying
6. I still have the appropriate winds to launch
7. final thumbs up from everyone.
Once those items are complete, the jet goes flying.
It's a pilot, NFO, or even an LDO sometimes that is a shooter. Why is because an aviator shooter has a certain kinship with the pilot and we understand the "safe for flight" concept in a different way. There are some basic aero issues that have to be understood to shoot a/c, so an aviator type already understands those concepts.
It is always an officer because of the rank/accountability of "pressing" the fire button.