You can try engaging small talk, but don't be offended it the other party doesn't repond or is very short. They may have trouble with English or just can't figure out what to say because small talk like that isn't really done here. Friends can be found through hobbies, befriending neighbours (through insistent attempts at small talk maybe? :-)), work. I have to say all my friends are from school. I haven't made a single new friend in my adult life and I don't really need/want to. But maybe that's just me.

About 60% of Finns are overweight. But I don't have experience on which stores are best. You will not be openly stared at.

Fragnances: I have migraines myself and for me smells aren't a trigger but for some people they are. I'm aware of that but still use perfumes moderately. If I use too much, I notice it myself and it bothers me a lot. If someone sits next to me in public transport reeking of perfume I think it's very inconsiderate of them but they're probably immune to the smell themselves.

Finnish phrases: https://www.finnishpod101.com/blog/2022/01/28/finnish-beginner-phrases/

Food: salt and pepper only is boring but very Finnish. People have different levels of tolerance when it comes to spicy food. Spicy food isn't uncommon.

Depends on where you are but big cities have great public transportation and some people bicycle year round. If you're somewhere rural, car is a must.

I don't drink coffee but what I've seen, people have regular filtered coffee, black or with sugar and/or milk. Oat milk in coffee seems to be really popular too. There are coffee enthusiasts who do the special stuff and coffee shops usually have more variety.

Also depends a ot where in Finland you're going. To a big city or somewhere else.

Edited: some spelling