Can I FOCUS an IP Camera?

..not really. Like point-and-shoot cameras, most IP cameras do not have a manual focus. This is generally not a problem however, since the objects in view are distant enough to not require focusing.

And also like point-and-shoots, you cannot vary the depth-of-field, aperture or F-Stop settings, so a shot like this would not be easy!

You can, in some cases, find alternate lenses for your camera. I've seen wide-angle, fish-eye and other options. Note that since these lenses tend to distort the photo geometry, they may not be useful for details like facial recognition, license-plate legibility, etc.

You can also sometimes find interchangeable lenses which offer other lens diameters.

What WOULD be nice, but I haven't seen, are UV or other filters.

I have noticed that some IP Camera controls do offer focus- so I tend to think that some manufacturers probably offer it. I haven't seen one yet, however.