Ive been through most of the areas you have mentioned and you should be fine. Ansonia, Derby and Seymour are all going through renovations to various degrees. The "Valley" as it is called has never been known for their schools historically, HOWEVER,(before anyone jumps on me) it has seemed to have gotten better. The towns do appeal to me though I can't figure out why?

You seem fixed on those towns so I won't try and talk you out of them as I know you can get a great deal on homes in that area. Do yourself a favor and drive around Stratford and try Shelton as well along the Housatonic.