
'Sani |

It depends on what your GM is going to allow.
If you are allowed archetypes from the Technology guide, you will both remove a great deal of mystery from the AP and become insanely powerful for it. I played Tech Slinger gunslinger in Iron Gods and while it was rather gimped for the first book, as soon as I got a tech gun it became so crazy OP it wasn't even funny.
From what I've seen barbarians do very well in this AP, as do anything that can cast lightning spells.

Saldiven |
Are you looking for your character to be very powerful, or merely interesting while still being relevant and effective?
I'm running a group and currently in book three right now, so I have a few ideas.
Are you interested in primary caster class (like Cleric, Wizard, etc. with 9th lvl spell access), or a caster/martial/support type class (Bard, Inquisitor, etc.)
You mention the wizard. Wizard can always be built to be effective, depending on what you want your wizardly role to be.

Arachnofiend |

WagnerSika |

Arcane bomber is a trap. You lose 4 schools, cantrips and arcane bond so you can throw some alchemist bombs. Yay. Why not be an alchemist?
I have had lots of fun blasting robots and monsters with Evocation Admixture wizard. Took a level of sorcerer to get some extra damage. 4d4+1 burning hands at level 1 is nice. Convert fire to electricity when faced with robots. I recommend Burning arc as second level go-to damage spell.
Standard Shocking grasp magus would be quite powerful for this adventure. Android would be cool as a race.
Human sorcerer with nanite bloodline would be interesting too.

Lanitril |
I don't think Arcane Bomber is that bad if you don't mind the spell loss. Know what might be better though? Regular Wizard VMC Alchemist. Maybe a level of actual Alchemist with it? Either Mindchemist or Inspired Chemist? Maybe even two levels for an alchemist discovery? Starts to get a little iffy at a two level dip, but could still be good.

Lanitril |
It should probably be a dip of alchemist and/or VMC, not just considered as and. In case that wasn't clear. If you can convince the GM to let you get Cognaten instead of Mutagen on the VMC, that's probably ideal and fair. It's very unchained. Lol. Just more so than the book already is.
Maybe one of the Urban Rager archetypes? Those could probably work really well in this as well. I've wanted to play a Urban Skald for awhile myself. Get that Dex up, particularly if the party leans more towards firearms.
Now that I'm mentioning things from Heroes of the Streets, and firearms, Eldritch Archer Magus could be really good too. Straight up amazing. Particularly with a firearm. It's not a tech archetype specifically, but it's ranged, and it's not limited to bows like the name suggests.