Thank you both very much. Xiandi, it was big help to know part of what was going on. Vampothica, I did try changing the state colors of those other buttons in that group as well; to no avail. I still have 3 small issues as demonstrated here:
1. Button is in pressed state. Text color for pressed and mouseover are the same and correctly displayed in this screen shot. Unlike Xiandi's Dark and Dirty skin where they are correctly displayed, these colors are not reflected in Firefox. The "post reply" button at the end of a post, for example, has black text color, and my bookmarks toolbar buttons display the grey text color as seen in 2.
2. The plus sign correctly displays the color for all states except mouseover, and pressed. I briefly used the grey in the minus box for the disabled state, but changed my mind. However, it is still displayed on all disabled state buttons I've found (including those in Photoshop), and as noted above. They grey is fine on the disabled state buttons, but not on the Firefox bookmarks toolbar. The grey color is nowhere in my chosen color states for these buttons, only the butter color, and the orangy color.
3. Button margins inconsistently disappear, especially with buttons in pressed or mouseover states. Oddly, where two adjacent sides meet at a corner, the overlapped corners do not disappear. Is there anything I can do about that?