Master Duel will handle all of this information for you, but this is helpful to know if you want to know why modifiers work the way they do
At the cost of 2000 Life Points, you can use any Fusion card in the game by sending it to the Graveyard
I also highly recommend getting some card sleeves to put your cards in before you place them into your binder for added protection
Specifically, Sword of Fire and Ice gets the nod in Legacy because protection from blue allows creatures to attack through True-Name Nemesis, red covers a section of cheap removal, and the trigger says draw a card. In modern I suspect many of the other swords will get their chance to shine: the protections are more relevant and cover different Modern archetypes
Roshan also turns all of your creature spells and cards that arent on the field into assassins as well, making it a great include in the 99 of an Altar Ibn-La'Ahad deck, or as the commander in an all-assassins deck if you like the deckbuilding challenge of being in mono-black
An ETB has 9 packs , not 36