I actually would prefer the Trick Room with minimum speed, because then you can invest some EVs in HP and Defenses, and if so, then the moveset would be:
EVs - 252 Defense/152 HP/104 Sp. Defense.
Calm Mind - This will let you have pretty good special stats.
Flamethrower - STAB, reliability.
Trick Room - Anything to say?
Energy Ball/Shadow Ball - Coverage or STAB? your decision.