Mulligans
So your goal is to go for C'thun, the Shattered for a Potential OTK. You need to use Gadgetzan Auctioneer as your Core Card Draw, and you need Nazmani Bloodweaver to discount as much as possible. Sethekk Veilweaver is there for Generation, so maybe you might want to trim out just 1 of them if you wish, and you also have Rally! to resummon all of them. You have a total of 4 Chances, along with Gift of Luminance to try and make more Nazmani Bloodweavers.
Xyrella and Youthful Brewmaster Are literally just there to get rid of Minions as you heal. So you have at least 2 Strong AoE Spells, other then Heart of C’thun, and G'huun the Blood God is there to effectively get C’thun for Free.