you can add any hops you want in both the inventory list and recipe editor and for anything else just add to the other in the inventory or custom in the recipe editor, you will need to know the details though so research those from the manufactures web site
When you add a custom hop with details can you then select that hop in another recipe or do you have to add all the details over again? the same query goes for adding custom fermentables.
you type in the custom your self, if cached in your browser it will come up again otherwise you will need to enter it over and over again, in other words no custom stuff is added to the database