Numbering to try to cover all of your questions...
1. Formula rear hubs have a long enough stock axle to space to 130mm.
2. The only difference between the 120mm formula and the 130mm is that the latter already has the spacers installed.
3. If you space the axle equally on both sides, the chainline for both sides of the hub will be right around 42mm (depending upon what cog & freewheel you use). Compare that to the distance between your chainring and the center line of the frame.
4. Front hubs are 100mm, virtually without exception.