Networking
Can I network with consultants outside the office I want to join?
I can't find many people from the exact office or region where I want to apply. Is it still useful to speak with consultants from the same firm in other locations and ask whether they can connect me with someone in my target office?
Ian’s Answer
Yes - 100%. Tell them you're interested in the company period. Then, when talking to them (and expressing further interest), ask if they might know anyone in the region you're looking to apply to.
Very low probability of working. I wouldn't do this, unless you can really send a killer email/message that truly catches their eye.
Not sure what you mean here. But, you should reach out to HR/recruitment, express interest, and ask if there's anyone you could speak to about x.
(Additional) Even try 3rd degree connections. A 2nd degree connection you have might have a bunch of contacts themselves in these companies