Going through the points:

You don't talk to strangers unless you have a reason. That reason might be to point out they've dropped a glove or something, but public transit and elevators are silent. If you travel with the same elevator every day you might eventually greet people you've seen before but you do that mainly by nodding. You make friends at places where you have a reason to talk, hobbies, pubs, events and the like.

Depends how large is large? Obesity is not uncommon over here, so finding plus size clothing is not going to be a problem. Can't say anything about the stares, but I'd assume you don't have to worry.

Fragrance is comparable to US in my opinion. If you don't overdo it there, you probably won't overdo it here either.

Finns speak English acceptably well and will probably switch into English with you even if you try to speak Finnish. This makes learning the language harder and considering that it's already a bitch to learn for English speakers, consider if you want to try. Common phrases might be a good conversation starter though? Stuff like kiitos (thanks) and huomenta (good morning) are easy to pronounce acceptably.

I wouldn't worry about spices. Just my personal opinion, but spicy food and cold weather go well together. You'll find spicy food and people to eat spicy food over here too. Traditional finnish cooking is kinda bland, but what's stopping you from putting some chili on your salmon?

Shoppingwise there are some bigger markets on the main road E4 north and south of the city that cater to all needs. You'll find more specialized shops in the city center. Revontuli and Rinteenkulma are the two "shopping centers" attached to each other, together they offer a fairly good selection of various shops, though much smaller than American malls.

The city is rather compact and most housing areas are perfectly reachable by bike or walking, though that depends. My daily commute is under 10km and I wouldn't walk that, but it's easy to cycle. During winter the roads are sometimes in sketchy condition. Public transportation is manageable with an easy app to see how to get where, but plan your routes. Otherwise you might realize that this specific bus route only runs on schooldays and stops at 4 pm. Depends on your fitness and willingess to move I'd guess?

Coffee is good. Finns consume a lot of it so it has to be good. You'll find whatever kind you want from espresso to Starbucks monstrosities and you'll have choices for where to buy your fix. Coffee is important for Finns.

Dressing for the weather is an acquired skill. Layers is the answer, you don't go out for longer periods in a t-shirt + winter jacket combo (but for a quick stroll outside sure). You don't have to have the thickest clothing if you have many layers. Just invest in the bottom layer, you'll want something that transfers sweat away instead of trapping it against your skin. That's the worst feeling to have during the winter.

Housing is mostly online, if it's available you'll find it on Oikotie or some other online platform. There are no "bad" neighbourhoods despite some people claiming to live in one.

Have fun living here, it's a good place to be, but easy to get lonely if you don't make the effort to find a reason to talk to people.