Yes, when you say παλτό - coat you mean something more formal, non-puffy, probably longer than waist outer garment, possibly with buttons. Something made of leather can qualify as a coat if it's the right design.
Anything else is a μπουφάν: all puffy stuff, sportswear, biker (leather or not) jackets, bomber jackets etc.
Edit: Changed "Anything else is a jacket" to "Anything else is a μπουφάν" to clarify what the words describe in Greek, rather than English, after reading BillDe's comment below. Yes, usage is different in the two languages, but, since (for whatever reason) μπουφάν=jacket and παλτό=coat, we need to make clear what the English words mean in Greek.
For neuter nouns in -ι, I think the stress always goes to the last syllable in the genitive case, both singular and plural.
For nouns in general, no -- the stress usually stays where it is in the nominative or may move a bit towards the end if the last syllable is considered long by Ancient Greek rules, but generally doesn't go to the end unless it was already at the end.
(There are some exceptions involving words that used to be first declension or that were third declension and had a one-syllable stem. It's all a little complex and historical.)
Yeah, I got a little frustrated when writing that comment, I guess :P I was also somewhat surprised that the typo I made (I think it was in writing "by" rather than "boy" or sth silly like that) resulted in getting marked completely wrong, rather than being told I made a typo.
Duo accepts a number of irregular sentences, lack of punctuation, lack of accents in Greek, missing spaces. It also accepts spelling error as long as the error isn't a word. Of course, if it is a word the Duobot does not know you didn't do it intentionally or that a "by" in that sentence made no sense. I've tested it on all of these even writing sentences without spaces.
Your question seemed to indicate that you objected to the word "anorak" since you typed it in all capitals adding a few question marks. Am I wrong?
Eh, I believe it was just a pretty frustrating session, where it took me more than 30 sentences before I finally finished. That happens sometimes, and I just felt like venting a bit because the error message wasn't what I was expecting. I know it's nothing out of the ordinary in the end :P
Yes, so did I but since creating this sentence we've since learned that "μπουφάν" has now become a rather generic term for any kind of winter outerwear. So, we've added some other definitions. I've recently been informed that we no longer call a 'blouse' a 'blouse' now it's a 'top'. And athletic shoes are now "sneakers'. Try googling "women's tops'' and checking out the images.