There is one or more haks that will remove the minimap that I've heard of, but not for just making in unavailable until a condition is met (such as with possessing an item).
For the compass, that one you could do a graphical override/hak to remove the visual (but it would still be there). Like the minimap though, "removing" it would mean it couldn't be turned back on in-game by possessing a certain item.
For both of the previous, this would also mean that a player would have to be using a hak file, and someone with basic knowledge of haks could easily remove the "overwriting" files from it to still see the map and compass in-game.
For the clock time on mouseover...that's one seems to be hardcoded. It's something I asked about several years ago on the old forum (I just wanted to change the text to display the name of a month instead of a number).
