1. You could I suppose remove any currencies you do not want to show in the currency table in phpmyadmin.
2. Not sure what shipping options you refer to. One can enter a shipping price to pay a seller but this program is not really a shopping cart you do not pick shipping etc
3. You would need to open a support issue on anything in the default code you do not think is working correctly like your avatar and as far as categories if they are listed as subcategories then I would think they are subcats by mistake
4. The only vb4 plugin for classifieds I know of is the one I created http://www.photopost.com/forum/class...-4-series.html