The core stock module is very basically there just to track stock on items. By itself, it does not do the 2nd and 3rd items on your list. That's where a contrib module would have to plug in using the stock values for a product to take action on the various pages. (The contrib Alaska linked to is also a more robust solution that you would use in lieu of the core uc_stock.module.) Shawn may be able to shed a little more light on this.