This is really great, thank you. Maybe I missed this bit but I noticed the guide doesn't touch on language issues at all, how hard is the transition for someone who doesn't speak Finnish?
Finnish is an absolutely atrocious language to learn for most people (unless you are already familiar with learning a language with a completely different root, and even then). That part will be hard. I can't comment on the practicality of surviving with only English (or even Swedish, which most of them speak due to historical factors that I will politely gloss over), because I haven't tried.
Of course I would like to learn more Finnish, but daily life and childcare interferes with regular lessons. (Of course being able to work in English also means that speaking Finnish at work is also difficult.)
Since moving to Finland four years ago I've bought a couple of flats, found a job, filed taxes, visited doctors, dentists, and similar things all in English.
I understand a lot of Finnish, I just speak less. Ordering food, etc, is something I'd usually do in Finnish although it has to be said a lot of people will either initially greet me in English, or reply to me in English which is a bit frustrating.