While a deck of any color identity can play War Room, it shines in mono-colored strategies
Its quite a strong ability that also lines up with Pocahontas character in avoiding battles and creating peace
Well, you'll either need to collect the cards from Arena booster packs for the sets they came in, or else directly 'craft' the specific cards you need using MTG Arena Wildcards - effectively tokens you can exchange for the exact Common, Uncommon, Rare, or Mythic Rare card you want, depending on the type of Wildcard
A creature with haste can attack in the same turn that it enters the battlefield
It is a lot more obvious when to use Oath than Traverse and a lot easier to play with which makes it quite a lot better in the archetype
Much like the main series, Pokmon come with their own list of elemental strengths and weaknesses, and can even evolve if you draw the required card