Can you make interchangeable lenses for point-and-shoot digital cameras (not DSLRs)?
As far as I know, you cannot change the optics of a fixed lens camera. It involves the substitution of a eletronic, mechanical and optical system that has the focus and aperture actuators.
You can, instead, use an adaptor ring and filters, like the "close-up filters" (look for +1, +2, +4 and +10 close-up filters on ebay), or the "fisheye filters", that are lenses that alters the viewing angle of your camera or minimum focus distante (and magnification) of the lens in your camera.
Those filters usually are low quality and introduces chromatic aberration to your pictures, degrading overall quality of images. And you need to find a adaptor ring for your point-and-shot camera (not all systems have a way to attach an adaptor and a filter).
Another way to get different focal lenght in your compact camera is using a tube fixed on the body of the camera, with the filter in one end, like the lenses you can use with a smartphone.
No you can't. Common point-and-shot camera lens can't be interchanble. But there do exist non-dslr camera that can change the lens - mirrorless ones.