Here are my thoughts:
Simple Slowking: No one is going to give Slowking two turns to set up TR and Nasty Plot, and without TR, it isn't any better than Manaphy. CM + Slack Off is still destroyed by physical attackers.
Water/Fairy Milotic: We don't have a Fairy retyping yet this month, and I'd like at least one to check the dragons.
Drizzle Bronzong: Milotic would have been an excellent rain starter, but that is not what we are voting on. Bronzong has no reliable recovery and no offensive presence, so it won't do much to help rain except give it a second starter to use in tandem with Politoed.
Psychic + Normal Reuniclus: We just voted for an Aegislash counter; we don't need another.
I'm going with Water/Fairy Milotic.