I didn't read all the posts but no sidearms that escalate the issue. The point is to diffuse and not engage. Get the survey and while that's in progress get a copy of "The Gift of Fear...Survival Skills." . This is standard stuff for cops and helps you identify just who in life is a threat and who is just full of it. My guess is your goobers are broke and have nothing but words and minor deeds to try to scare you away. Read the book.
The goal here is no escalation. Do the survey, flag it and avoid them. If you have any unintended contact be carfeful with threats. Just don't make any. If they threaten you make notes and tell them you do not want to escalate the situation and don't want to call the sheriff but good fences make good neighbors and the issue is pretty clear here.
If they had a reasonable sense of the law they would never have blown grass on you or your side. That is truly stupid and reveals their ignorance of issues that matter. Do the survey, read the book, no escalate and keep growing those concord grapes.