What's the word for "stationed", but for non-military people? I am thinking about non-military personnel such as ambassadors, and other non-military people working abroad.
You have used the word "stationed" This is technically incorrect although it commonly spoken. "stationed at" would be correct. The word you are looking for is Posted and it applies to both Military and civilians.
post verb (PLACE) to send someone to a particular place to work: Cambridge English Dictionary
He's been posted to Pakistan for six months.
post noun (JOB) a job in a company or organisation:
Teaching posts are advertised in Tuesday's edition of the paper.
She's held the post for 13 years.
They have several vacant posts.
post noun (PLACE) the particular place where someone works, especially where a soldier is told to be for military duty, usually as a guard:
The soldier was disciplined for deserting his post.
I was ordered to remain at my post until the last customer had left.