Or is turning into a fault the same as deleting that thing completely? I mean... is that guy then just still alive as a super lightweight object with no big data inside, or is it actually deleted?
Or: Is a fault an object in memory with low footprint, or is that a "virtual object that COULD be there, but isn't yet"?
No, definitely it's not the same thing as deleting the object. Moreover, there is no guarantee that it will be flushed back to the filesystem nor there is a guarantee that it will be removed from the cache. For instance, assuming the object has no changes, nothing needs to be written on the filesystem, and there is a chance that, instead, it will remain in cache.