For amber lighting, I have seen both.
Here in California, Crew transports, with Cal-Fire have all red, and will go code-3, with inmates, to a fire. Its kind of a neat thing to see seeing 3-5 at a time all going code in a convoy.
Bulldozer transports from Cal-Fire, also have red and DO go code-3 as well.
Now water-tenders (tankers) on the other hand, varies by department, some go code some have all amber. Riverside County Fire (contracted with Cal-Fire, changed all their tenders about 15-20 years ago from all red to all amber. Now they do not respond code to the scene and the amber is for scene safety while they are out playing in the mud
For contractors, even out here, some contract for bulldozers, even planes and helicopters.
For inmates on a fire, they are trustees, and granted escape attempts are attempted, most are good hard working guys, and go through wildland fire training and have their certs.
A lot prisons and correctional facilities, in the nation have fire crews. Right now I have a friend who is a Corrections Officer with Nevada DOC, and he is assigned to a conservation camp in Nevada that is just for fire crews. He is telling me right now they have a few crews out with NO OFFICERS with them. They are signed over to the fire strike force and it becomes their responsibility.