Sorry it took me a while to get to this; I have been indisposed.
A. Unfortunately you can't display tags on S1 style layouts because IJ is cruel so cruel :( That feature is only available for certain S2 style layouts like Bloggish.
B. Absolutely! Just find the part of the layout that begins with .entrybox .index and add a font size to it. (ie. font-size: 8pt) and the user names should display fine. You can also change the font color in that section as well to whatever color you want the usernames to be.