From where and how did the Excalbians create the humanoid fighters?

Question

In "The Savage Curtain," an Excalbian (or several) forces Kirk and Spock to participate in a "good vs. evil" war. In addition to the two Starfleet officers, the "good" side consists of Abraham Lincoln and Surak; the "evil" side is represented by Kahless, Zora, Genghis Khan, and Colonel Green.

Where did these humanoids come from? Did the Excalbians cause the Enterprise crew to hallucinate? Did the Excalbians literally create life? Were they facsimiles of the individuals, like the Douwd's copy of his wife?

Answer 1

We know that the Excalbians are shape-shifters (source). I suspect they used this ability in the experiment, as supported by the previously linked StarTrek.com article, which says:

The Excalbians are capable of shape-shifting, and use this ability to experiment on the social practices and belief systems of passing alien life-forms.

However, it's quite unlikely that the Excalbians were the actual participants in this; why would they participate if the purpose was to ascertain the difference between 'bad' and 'good'? That defeats the point!

Rather, I suspect that they used their shape-shifting abilities to manipulate the objects in their environment, making them take on the shape and likeness of the humanoids we see. Indeed, it seems that they did 'create life' out of something other than themselves. They seem to have the power to read the databanks of the Enterprise's computer, so why not also be able to shape-shift matter into animate humanoids!