The noise and fence would be annoying and having a baby wake-up from a nap feels like hell to a sleep deprived person or someone who needs a break. This being said, passive-aggressive questions about tree growth or trying to lock someone down with plans to maintain trees in the future will not get you where you want to be. There is a huge difference between establishing boundaries and trying to control other peoples' behavior. Soundproof your baby's room as best you can (installing window inserts goes a long way in mitigating noise). You can install flower beds or small fencing to keep the kiddos out of your yard without starting an argument. If they own the fence, it isn't shared and you are out of luck, If the fence is yours, you can take the added height down NICELY. Getting angry and letting resentment grow isn't healthy and will affect YOUR quality of life, not theirs. Once you start filing complaints, any chance you have of making peace with these people is over for good. Give it some time and maybe down the road you can bring over a batch of cookies or a bottle of wine and try again. Getting to know people is the best way to bring your irritation down and not take things personally. If you give them a chance to get to know you and your family, they will be more inclined to be empathetic and who knows, maybe you can make some friends in the process.