Mulligans
Aggro Mulligans
Frostbolt to kill Knife Juggler or something like that. Mad Scientist avoid to pay a secret and can add 8 armor who is very usefull vs aggro. Arcane Intellect is here to drawn the cards to tempo and the turn 9+ combo.
Midrange Mulligans
Keep in mind you have the combo (Frost Nova + Doomsayer) at turn 5 to stop the develop of the midrange game.
Control Mulligans
Here no need to use the coin. Draw if you can play thaurissan turn 5 with draw or the combo in hand its clearly win. Be carefull againt warrior (armor) !
The goal of the decks is to wait until you can play Alexraza -> Frostbolt/Ice Lance (+ Antonidas) -> Fireball -> Pyroblast. Thalnos help to draw of can be added in the turn 9+ combo.