Nice images. All look to be type 2s. Note the raised edges. That's caused by what's called an upset mill. The mint does that to make the coin strike better. They are called blanks before they do this and planchets after the process. The slight difference in look of the edges of a planchet is not important. Cool to find that many in one place.
Yes nice images! I think I understand what you mean by that 3 sided appearance.. that's normal for a pre-struck Cent.
Ok I figured it would be irrelevant. As I was going through them I noticed it was only 4 out of the 20 that had it so I wanted to make sure. Thanks. Taken with my Galaxy S5 cellphone lol