The last one, showing an 8-point sunburst (or flower) surrounded by 14 stars on a stippled background, is a type which button-collectors call a "Fashion" button, made for use on civilian clothing. They can be extremely difficult to date with much accuracy.
I have to say, in nearly 40 years of closely observing pre-1900s buttons, I've never seen the specific sunburst/flower-&-stars-&-stippled-background emblem on your button.
I seem to see some rusting on its backside ...but absolutely no rust on its frontside, which looks silvery in the photo (which may be just due to the type of lighting used for the photography). I can't tell from viewing the photos whether its body is made of brass or of iron or some other metal. It may have a brass body with an iron loop. Please use a magnet to check the body and the loop, and let me know if it sticks.