I do not have a specialized Russian catalog, and Scott is not the best reference for classic stamps.
Stamps below are both Scott # 26 based on Horizontally Laid paper. Based on Scott the background color is red as on the left stamp. The stamp on the right looks more like salmon. Is there any listed shades of this issue in specialized catalog, or this is simply a faded stamp.

This pair are both Scott #42 based on HL paper. Most of the stamps of this design look like stamp on the left. The stamp on the right looks like have background recut. The lines around the eagle are much thicker, and broken in many places. Again my Scott is quite about it.

This is going to be a tough one. Notice a green overprint at the very bottom of this Scott #19. Any ideas?, part of the cancel, revenue, local, commercial?

