Fang clamps are intended to be used with "softer materials." So most all woods, plastics even stiffer foam.
Potentially. They are made from Stainless steel but not designed to be used with metal stock.
Yep, although minimal. They are intended to be a "biting" clamp for OP0 or OP1 workholding. If you have exceptionally soft woods like Redwoods they will dig in further.
Yep! Every Fang Clamp set gets a hardware kit included