Mulligans
Even Shaman is particularly good in the Brawl “A Brawl of Fire and Ice” since one of the strengths of the decks is maintaining control of the board.
Neither Ragnaros or Ahune is very good a clearing a wide table so as long as you focus on winning the table on the first few turns this fight becomes increasingly easy, as you will have a large board to buff once you receive the Fire festival card.
Whenever possible avoid leaving a minion at 1HP (the only minion that “naturally” has 1HP in the deck is Searing Totem)
If you get Wrath of Air Totem on T1, a T2 Spirit Claws will be VERY helpful in keeping control of the board.
It worked after adding a couple 0/4 healing totems. Disappointed no extra packs for defeating them both.