Gold adds warmth, Silver increases contrast/brightness, White provides neutral fill, Black blocks light (negative fill), and Translucent diffuses harsh light.
Yes, it uses a 'twist and fold' mechanism that collapses the 42-inch frame into a compact 15-inch circle in seconds.
This rental typically includes the reflector and carrying bag; it can be handheld or mounted to a light stand using a standard reflector clamp (sold/rented separately).