I did a tiny amount of digging on the DV issue. It's harder to research, because while public health is a statewide issue and thus the state must publish regular reports, domestic violence is usually a county or local issue and I don't think there are state agencies that composite the data together.

I did find some stuff on DV-related homicides. Those have gone up since 2004. However, I don't see how that can be claimed to be the result of gay marriage; the report was one page and didn't break it down by the genders of the couple. In 2007 there were 55 DV-related deaths, by the way: 42 murders and 13 suicides in 37 incidents. (It counts children being offed.)