Hi Frank, in answer to your questions:
1) Multi-currency support allows for ad owners to choose the currency for their ad. If you're looking to display multiple currencies at the same time, then yes this would require some modification of the default theme.
2) If Google maps supports your country, then the location will still display even if you don't have an actual post/zip code, as you can complete other relevant location fields.
3) Yes, we're still aiming for this to be the case for all themes. Thanks.