You need to check your deed description, the title to your property and local ordinances. There is no universal answer to your question but property lines are usually the boundaries described in your deed. In many cases there are recorded surveys that show property lines.
yes you can but you have to be careful where the foundation wall sits. And the thickness of the footing has to be doubled and the projection cannot be on the other property.
bathroom wall, window
You haven't added what exactly the neighbor has to pay for.
If the concrete wall, fence or other structure is clearly on his side of the property line, the neighbor can do just about anything he wants. It's his property, and as long as the structure does not encroach onto your property, there isn't thing one you can do about it.
It will be close to the inside wall where the water supply passes into the house from the line going towards the water meret.
If you have a basement, you can see where the line goes through the wall. It is probably a straight line from that point to the street or alley depending on where it is. If in a group of track houses, it may angle to the property line and those two house will run in the same ditch. It can be anyplace, there is no set place it has to be, only the depth. If you don't have a basement, you can use the same directions and go from the main vent in the roof.
why the wall of the house is important
Often times a wall is on one or the other's property to avoid this issue. You will need two things in this case. A new survey of the land to know exactly where the property line is in relation to the wall, and a good attorney, so he can file the temporary injunction needed to delay any damage to the wall while this is settled. If that is done, the future court argument would be that given the length of time in existence, there is some kind of implied easement.
Not AS the wall of a house but it can be used as part of the wall of a house (as insulation).
A party wall is a wall that divides two adjoining buildings or two adjoining units in a building. In the case of buildings, it usually lies along the boundary line that separates the properties. In the UK a party wall can be a garden wall that runs along a property line. One owner cannot do anything to the party wall that would damage it or affect the intregrity of the wall. See related link for information about the Party Wall Act in the UK.
Your question requires a lot more detail. Generally, you cannot build a wall that would restrict access to the area of the property subject to the easement. An easement allows people other than the owners of property to use the property for a specific purpose (commonly easements are granted to give neighboring property owners access to a road). If you recently purchased the property subject to the easement you are not allowed to build a wall which would restrict the easement owner's access to the property.If you are asking if you can construct a wall on the other side of an easement upon property you do not own, the answer is no. You have the right of egress and possibly to maintain it, but does not give you the right to construct a wall on the ajoining property outside of the easement which you do not own.See discussion page.
I would venture to say that a fence is either more temporary or constructed from materials, other than concrete stone or brick.