The only difference between a colored artifact and a colorless artifact is, obviously, its color. Unlike most artifacts, a colored artifact requires colored mana to cast. Also unlike most artifacts, a colored artifact has a color in all zones. It will interact with cards that care about color. Other than that, a colored artifact behaves just like any other artifact. It will interact as normal with any card that cares about artifacts, such as Shatter or Arcbound Ravager.

The Homunculus you sacrifice due to the second ability isn’t limited to being a Homunculus token put onto the battlefield by Puppet Conjurer.

If you control no Homunculi when the second ability resolves, nothing happens. There’s no penalty for failing to sacrifice a Homunculus.