Are these any good? Let's try them out!

Mulligan

Winning is easy with this deck. All you have to do is not die. However, the not dying part is a bit trickier. Therefore, you want to hard-mulligan for every 2 or 3 mana card in your deck except Brann. These cards hopefully help you to stay alive long enough to stabilize.

Ideally, you want to combine a Doomsayer with a Freeze-effect, but don't hesitate to throw him out there as soon as you can when you face an aggro opponent.

General Strategy

Blizzard, Luna's Pocket Galaxy, Deep Freeze, and Puzzle Box of Yogg-Saron are your big spells in this deck while Dragoncaster, Clumsy Courier, Tortollan Pilgrim, and Kalecgos are all here to cheat them into play and Grey Sage Parrot is obviously here to repeat one of these big spells.

Both Alexstraszas are used as finishers, especially when combined with Brann after all have been discounted by Luna's Pocket Galaxy. Additionally, alongside Kalecgos both Alexstraszas are also there to activate Dragoncaster's battlecry.