No he's not Flagg. They are two completely different characters. Flagg was a lonewolf he took care about himself only, Linoge was looking for a heir. Then Flagg was powerlust he loved to manipulate people, Linoge was
focused on his goals only. They are absolutly different.
And yet, I think the town should not give Linoge what he wanted. I think Mike was right - Linoge would just go away if they refused him. But they did exactly what he wanted and it gave him the power over the town.
The more they believe him then the more his powers grow. So I think Mike was right, he's the one who was right. Mr. King did not tell it directly but some events in the end of the story point out on it, like the suicides of some residents.
I'll have to look again, but I think they might be from the Old Testament, as well. Something is dinging faintly in my head about black and white stones being used by Hebrew priests for something. It's been a while since I did an OT study, so I could be wrong. Research required
EDIT: Yes! I remembered correctly--lol. In the Hebrew Bible, the Urim and Thummim (Hebrew: האורים והתומים, StandardhaʾUrim vəhaTummimTiberianhāʾÛrîm wəhatTummîm) are associated with the hoshen (High Priest's breastplate), divination in general, and cleromancy in particular. Most scholars suspect that the phrase refers to specific objects involved in the divination.
In more modern times, they're a reference point for Mormons, as well.