#1 If I point it through a 1-1.5 inch thick steak, can it detect a single stainless steel bristle like those found on a bbq brush cleaner?
That is a hair like piece of steel and most likely would detect at about 3/8" to 1/2" with the Little Wizard. For the deeper distance you would need a commercial grade detector and those start at a couple grand to about ix grand a piece. They are AC powered very large table top style needle detectors for food processing.