Suggested Lighting Equipment And Set Ups

A small documentary where portability is paramount - Sun light, ring light attached to the camera, small box lights

All of this equipment is small and light making it easy to carry around as you move from location to location for said documentary. The ring light attached to the camera will help keep areas in front of the camera well lit and the small box lights will help light up more shaded areas the the sun can't reach. The only issue with the sun on a bright day is as you move from shade into sun light it can make keeping the light exposure levels consistent and can cause people on screen to squint. to help resolve this, you could either keep to shaded areas, have the people on camera face side on from the sun so they don't squint or plan ahead and shoot on a cloudy day or when the sun is at a high point in the sky which would keep the lighting consistent and away from eyes.

Talking head style interview - Full studio soft box lighting kit -

This lighting is what is used in the majority of head style interviews as the subject usually stays in the same spot. This will mean you wouldn't have to move heavy equipment around and the lighting and exposure levels would stay consistent throughout the shoot.

A night time shoot - Natural lighting (cities) and ring lights.

I would choose this equipment for a night time shoot as the ring lights will help keep what's in front of the camera stay well light in dark areas whilst also keeping the "night time feel". I would also use natural lighting from the cities as unless you're walking around into unlit areas at night the exposure levels and lighting would stay fairly consistent throughout the shoot.