Vasodilation does not necessarily increase (nor decrease) inflammation. Expanding the blood vessels simply allows blood to flow more readily. If the body senses a trauma, it will vasodilate locally to increase the blood (and leukocyte) flow to the area. If there are a lot of broken smaller blood vessels (capillaries) around the area (after being hit by a pitch, for example) then that increase in blood flow will pile up and cause inflammation. If however the body is very cold (or very hot for that matter) vasodilation will occur so that the temperature of the blood from the heart can heat up (or cool) off those cells to bring them back to their ambient temperature. This will force that lower (or higher) temperature blood away from the site, and so this could have either anti-inflammatory effects or no effect.
So basically vasodilation is the MEANS for EITHER pro- or anti-inflammatory effects. With laser we take advantage of both (whichever we need). If its a neuropathy, when we laser we will bring more nutrient-rich blood to the nerve endings and put a stop to the pain. If its a contusion we will take dirty blood away from the site and decrease swelling.
My answer to "is it pro- or anti-inflammatory and how?" would be...
...All the other chemical changes mentioned are the body's responses to the condition. So whichever helps the particular conditions, whether that be increasing or decreasing those enzymes, that's what the body will do, once it has made enough chemical energy (ATP) available to carry out those processes.