From my POV you can go two routes; Poison or Fairy. A Ghost type would also be a viable option, but with Alakazam being weak to Dark and Ghost at the same time, I feel it would repeat too many weaknesses.
Good defensive wall, very useful ability allows it to have only 1 weakness which both Zoroark and Alakazam can cover, and good movepool (Will-O-Wisp, Pain Split, T-Bolt, Fire Blast, Sludge Bomb).
Good special wall, useful abilities in either Clear Body (counters Sticky Web) or Liquid Ooze. Access to Rapid Spin and Toxic Spikes, and can also absorb Toxic Spikes on switch in. Electric and Ground weaknesses are, however, not covered by Zoroark or Alakazam.
Since you have a noticeable Bug weakness, I wouldn't recommend Drapion, as Bug is only neutral, on top of Fairy also being neutral.
Very good special wall, along with good support movepool (Aromatherapy and Wish), as well as good STAB (Moonblast) and decent base sp. atk.
Very good physical attacker with Huge Power, which would go well alongside 2 special attackers. BellyJet set or Band are both viable, but Grass and Electric weakness aren't covered by Zoroark or Alakazam.
Can be either physical or special wall, and has good support movepool (Wish and Heal Bell), with Magic Guard being a very good ability to absorb status conditions and immunity to entry hazards.