1. Yes
2. I am not sure, I would say yes so long as it is the spell and not like. Usually supernatural effects are very different than their spell counterparts. An example would be a cone of cold versus the White Dragon's breath weapon. While they may produce a similar effect and White Dragon's breath weapon constantly scales in strength and effectiveness to the amount of hit die it has. A cone of cold spell maxes at a caster level of 15 and the DC is dependent of spell level. So if a White Dragon didn't have a cone of cold in its sorcerer's list of spells known it can't make an item of it even though it has a much more powerful one available to it naturally.
3. No, the magical device has its own power and set of components. All you do is direct it and turn it on. Using a magical item doesn't mean you have full knowledge of the spell.