Nice Finds. I will take a stab at the brass pieces. The brass piece with the rectangle holes in it is a Harmonica reed. I see a brass shell casing.. and the Brass piece under the shell casing appears to me to be a keyhole cover off of an old lock or door lock. Top piece of brass with hole drilled in not to sure about that one. Great finds for sure. Keep on Digging.
That looks like a trigger assembly of some sort... 
