Three in one: iray decal, an instance and find by type

Hello, I've accidentally found script ide and it gave me an idea to speed things vastly. I'm completely new about it.

I've a few questions to get me started for my project:

1- How can I create an iray decal via script?

I've searched the forums quite a bit, but couldn't come to a hit for creating an iray decal via script. By also looking at object index doesn't ring any bells for object creation.

2- How can I create an instance of an existing object via script?

I need to create instance of an existing object. Then I will manipulate it (move-scale-etc I think I can handle this part).

3- How can I confirm a type of object is e.g. Null?

I need to filter or loop by type of objects. For example, what gives me back "Null" via script when I was iterating through objects?

I want to achieve something like: if ( typeof (itemBeingIterated) == "Null" ) { ... } or something like if ( typeof(selectedItem) == "Decal" ) { ... }

Any help will be appreciated, thanks!