
McDaygo |

So I am looking to build a character that primary attack mean is weaponizing mists (Insanity/horror mist). The idea is a mixture between Mysterio and Scarecrow. Can't decide if I want to go Sorcerer with an illusion/horror bloodline or alchemist and focus the extracts more on the illusion side this way we can fast create his own mist cartridges and have bombs for back up weapons.

Pan, definitely not a Kitsune |

I'd probably go with sorcerer, psychic or possibly even (that spontaneously casting) witch.
Spells that seem perfect:
Haunting Mists,
Euphoric Cloud,
Mind Fog,
and the reason I might even suggest witch: Barrow Haze
These seem to fitting to ignore.

Pan, definitely not a Kitsune |

There's a poisoned sand tube or a toxic censer.But as usual, the mundane options are severely restricted, which is why I'd definitely go Caster. Poisons aren't useful, and drug rules are a dangerous mess.
As an aside, this alchemist archetype is probably… mostly useless, but might still be thematically appropriate?

Pan, definitely not a Kitsune |

Personally, I'd still go with sorcerer because they can pull "scary or poisonous gas" off with spells with less investment while being better at it.
That being said… Alchemists have some neat toys:
Aromatic Extract (Heroes of the High Court pg. 10): The alchemist creates an inhaled version of an extract that is shared among multiple creatures. He must decide that an extract is an aromatic extract when he makes it. When used, the extract grants its benefit to all creatures within a 10-foot spread of the extract. The aromatic extract is treated as having the minimum caster level required for the original extract. An aromatic extract expends one of the alchemist’s daily extracts as if it were an extract 2 levels higher. This discovery can be applied only to extracts with a range of touch. An alchemist must be at least 10th level and must have the infusion discovery before selecting this discovery.
Poison Conversion (Ultimate Combat pg. 24): By spending 1 minute, the alchemist can convert 1 dose of poison from its current type (contact, ingested, inhaled, or injury) to another type. For example, the alchemist can convert a dose of Small centipede poison (an injury poison) to an inhaled poison. This process requires an alchemy lab. An alchemist must be at least 6th level before selecting this discovery.
That last one is relevant because of some special rules for inhaled poisons: "Unlike other afflictions, multiple doses of the same poison stack. Poisons delivered by injury and contact cannot inflict more than one dose of poison at a time, but inhaled and ingested poisons can inflict multiple doses at once. Each additional dose extends the total duration of the poison (as noted under frequency) by half its total duration. In addition, each dose of poison increases the DC to resist the poison by +2. This increase is cumulative."
…which is one of the few ways to keep poison DCs relevant.