Any suggestions for what piece “Strahd” might be playing on the organ in K10?

Have any tips on running Curse of Strahd for 8 players?

CoS Spoiler – Is the vestige that broke free in the Amber Temple a nod to something at all?

Anyone have ideas on how to run Arabelle as an ally in Curse of Strahd?

At which point/how often would you have Strahd appear to PCs?