In order to identify these properly you need to know the perforation and the watermark first!
Note that the OP scrambled the front/back row order so that the top row in the front image is the bottom row in the back.
Lets answer the question based on the image:
1. It is a flat plate perf 11 Scott 554. Small flecks of ink, called setoff, can be seen in the back image. The top and side perforations would match in Photoshop.
2. Perf 12 two cents is either a Scott 332 or 375, probably the latter because no double line watermark visible in the back image. The stamp should be dipped to confirm that it has a single line watermark.
3. Perf 11 booklet pane single, Scott 554c. The appearance of the stamp design is noticeably square compared to example number 1.
4. Perf 10 Scott 428. Some traces af an "S" single line watermark can be seen in the back image. The stamp should be dipped to verify that it is watermarked.
5. Perf 10 rotary precancelled Newark, N.J., Scott 583. Gum breakers can be seen in the back image.
6. Type III double line watermark (visible in image), Scott 267. The right side of the "T" in "Two" is curved.
I don't see the benefit of sending inexperienced users off to fend for themselves without some initial guidance.