Generally the term "fresh" sausage is used for a sausage that remain un-smoked when they are made. Specific styles of sausage need to be smoked as part of their production process however other styles of sausage do not. It is all to do with the style of sausage that you are trying to create. Sausages can be frozen whether they are fresh or they are smoked.
The poaching of the sausage does a couple of things. Firstly it effectively cooks the sausage and gives the it appropriate texture for that particular type of sausage. Secondly, providing it is taken to the appropriate internal temperature, it will kill off any bacteria and therefore extend the sausage shelf life. Unless the sausage has been cured it will still require freezing for longer term storage though.
You could smoke your sausage after it has been frozen however I don't think many people would do that. Most will finish making their sausage completely before freezing so that it is more convenient to used when thawed. There may however be an arctic style sausage that does require freezing before smoking - and if there is I am sure that someone on here can enlighten us.