It depends on what you mean by surveying your property. Most laws allow a surveyor to access abutting property as necessary in order to survey a common property line. Therefore, yes, a surveyor can survey your property line where it abuts your neighbor and make any calculations necessary to set a legal property line.
is it legal to video a neighbor on their property without proper legal consent
Refer to your survey. If you have not had the property surveyed then that will resolve the dispute.
This may be a situation that will require legal intervention. The first step would be to have the property in question surveyed. Then you could proceed with legal action.
If the fence is on the legal, surveyed property line, then the line is official immediately.If the fence is not on the legal, surveyed property line, your state's doctrine of mutual acquiescence will determine if and when the fence will become the line. A real estate attorney in your area will be able to tell if you have a legitimate mutual acquiescence claim.
yes
Get a survey and prove it is indeed your property then seek legal counsel.
If neighbor A took down a garage and it caused the neighbor's retaining wall to fall, they (neighbor A) should be responsible for cleaning up the mess. If the rocks are on neighbor A's property, they can place them on neighbor B's property. A judge can decide who will actually pay for the cleanup.
Have your property surveyed.
No. In that case you should report it to the local police.
Yes, because it is on your property, and is now your responsibility, since it is on your lawn, and not on theirs, it can be yours because it is on your property.
In short... No. Your neighbor should have tried to find an owner (you) or at least called the police to report found property but he does not have to do this if someone else's property is left on his land.
A boundary line is the dividing line between parcels of real property. It is sometimes a line that is surveyed according to the property's legal description, and sometimes the result of adverse possession (see link below).