For the first request - that can be done by events very easily. Make a common event and have the item, wallet call that common event. In the common event, put this:
@> Control Variables: [XXX: Gold] = Gold
@> Text: \gYou have \v[XXX] Gold in your wallet!
For the other two, both of those are very simple. If you look around you will probably find a faces in menu script, and the status screen is a simple matter of drawing the battler before the text. Both are very easy, but I don't have time right now. Remind me if nobody takes those requests.