Which one is the one involving Sami wizards?
Nothing comes to mind, sorry! Not that having a party on the roof was rare, just that usually it was done by ghosts. I'm curious too so I'll look more into it, maybe I'm just overlooking something here.
Wyrm, I think in the context it was more implied that the 'wizard' put a more - permanent - end to the dispute. For one thing, the Finns were notorious for weather magic, which in a seafaring culture can do great damage for minimal expenditure of power. All those folktales where the sailors buy a bag or knotted rope containing winds from a Finnish mage, then somebody gets impatient or messes it up.....
Damn, wish I could remember which saga it was! Hate it when I forget things!
I can look into this one too. The wizard they hired was likeliest a Sami though, as back when the sagas were written Sami people were called Finns. The people now called Finns weren't one people at all but a group of tribes, each one bearing their own tribe name, and to this day Finns use these area-coded names (and call these groups tribes,
heimo). For example I'm a Häme girl because most of my family is from Häme, but I also have a Karelian side because that's where my grandma on father's side came from.
Eyjafjallajökull is simple! It's phonetic.
You just eyja - fjalla - jökull
Don't forget the double L sound and the vowel length rules though, Icelandic is rarely phonetic.

Eyjafjallajökull = eyya - fyathla - jöökthll.
EDIT oops skipped over one:
"Greenland is horrible, but you have persuaded people to move there with false advertising".
Somehow this reminded me of the Silent World and Sigrun seeing it as a vacation. Course, for her it was...
Grænlendinga saga, or Greenland Saga.