[Maine Mariner]

Your point #2 is the interesting question.

Do we ever see low information voters turn out in large numbers to vote in a Republican primary run-off election?

[Viennacon]

Not typically, BUT we have seen that Cochran has actual black Democrat organizers working for him. How effective they will be remains to be seen.

[Theodore R.]

Do we ever see low information voters turn out in large numbers to vote in a Republican primary run-off election?

I can't think of one. Maybe the 1980 U.S. Senate runoff in AL, won by Jeremiah Denton, but I don't know if his voters were "low information". And I don't recall who Denton beat.