“1) The Sheriff is the de facto head of his counties’ militia in Common Law.”
No, he is not. He is elected for law enforcement which is not the militia in any way. Common Law has also been outlawed in several States including Colorado. For Colorado, 1972 was the year I believe.
https://en.wikipedia.org/wiki/Sheriffs_in_the_United_States
“Historically, the sheriff was also commander of the militia in that county.”