The extended family situation sucks, no doubt and can develop at any time. Best to be avoided if at all possible.
My last neighborhood was fantastic when I moved in, all new homes, everyone kept up with everything but as we got older alot of families moved up and out and alot of renters moved in. With that the lawns go to hell, weeds don't get taken care of, POS's and trailers on the street.etc. My personal peeves. I made sure I moved to a hood with an HOA, lots of people don't like them but I do. The downfall to my old neighborhood though was my next door neighbor, my good buddy put his house up for sale, a week later for rent, and then everything went to hell, he and the state were in kahoots and the house next to me became a Section 8. I don't know if you can find out if any of those are on your new neighborhood but it would pay if you could find out.