I think for the last one, most likely is the CCD. As for the others, might be due to dust on the lens. If you use smaller apertures, the dust will be more visible. If you use bigger apertures, it will not be so visible, or will not be seen. Just my opinion.
Just saw some flares in some of the photos too. Putting on a lens hood might do the trick, or don't shoot into the light. Correct me if I'm wrong.
lens flare. you'll get that if you aim into a strong light source. Regardless of whether you're using a lens hood or not, you cannot prevent flare if you aim directly into a light source, the flare will show up in the darker regions.
Lens flare. Quite inevitable if you shoot into the light. Filters will make it worse. Lens hood can help reduce flare from light source from the side, but are useless for flares caused by light source you are shooting into.
What lens are you using? The flare is consider quite controlled already.
The only way to remove it is during post processing.
The little light patches all over is contributed by the lens, but that consistent purple patch in the center could be a problem with your sensor. It seems to show up in the center whatever position the light source is in the picture.