1) Did you already download the extensions available on this page http://www.beersmith.com/data_updates.htm
Note, once you open the BSM file in BeerSmith, you have to drag the items into your Grains or Hops or whatever folder. If you don't drag them over, they'll disappear when you open another BSM file.
3) Yes. In your recipe, double click the hop you want to modify, and it has a selection for "Form:" and you can choose pellet, leaf or plug. You can also modify the default by making the same setting, but in your Hops Database view, not your Recipe view.
skipping 2+4, not sure...
Hope this helps...