There's one more important Iceland detail to this though: traditionally there are many kinds of magic-wielding people in Iceland, but for Icelanders not all magic is magical.
For example people who get visions in the dreaming, be they of the future or the current events (f.ex. using the dreams to find something that's lost) are not the same as people who know and use runic magic, or people who use seiður. The dream-using people are considered normal, everyday people who just so happen to have that talent, and they're called
skyggn. Just because you're skyggn does not mean you're a seiðkona/-karl.
Runic magic is something that anyone can use but it demands a lot of studying. Magical staves in particular are not just scribbled here and there whichever way: they usually come with complex set of instructions on not only which direction they have to be drawn or carved but also what they have to be carved on and what else needs to be done. The use of staves does not automatically have the effect you'd think it does, and people's view of you might be quite negative depending on how you use them.
As an example there's a stave called
óttastafur, terror stave. If you carve it in the right direction on an oaken shield and then throw the shield at the feet of your enemy he'll be seized by terror and either freeze on a spot or flee. If you fail any of the instructions the stave either won't work at all or worse, it'll work against you. However, even if it would work your reputation will be in the ruins because you've just demonstrated you don't have the guts to go against your enemy without leaning on unfair tricks.
There were of course all kinds of staves. There were those that were carved on tools and then filled with the user's blood, to f.ex. make a rake faster to use.
Farming tools, fishing tools, that sort of thing. There were staves commonly used to battle harmful magic or magical creatures. There were those used for good, healing for example, and those used for bad such as love staves - love staves were counted among attempting to cause grievous bodily harm and the punishment for the use of them could be death, if they worked. Egils saga has a story of a young man who gets turned down by the girl he has a crush on and attempts to use love staves to win her over... only he makes a mistake carving them and the girl gets deadly ill instead. Another such story is of Jón Jónsson the younger who was burned at a stake for using fart runes against a woman who turned him down.
Seiður users were commonly women and the practice was seen as extremely feminine, although the biggest seiður user of all times was male - Odin himself. Seiður requires both talent and a vast knowledge, and on occasion the help of other seiður users as there are things a single magic-user cannot accomplish alone.
And then there are the vala/völva, prophetesses. They used seiður too but were especially good at seeing the future and were given a lot of respect by the community. They not only were knowledgeable on magic but history as well and had proven their skills at prophesy many times before.
SO after this looooong rant: Árni may have been skyggn. He may have had talent for all kinds of magic, who knows, but if he never studied magic it would come to nothing and others would only view him as one of them skyggn people/a bit weird/crazy. Reynir most definitely seems to have the talent, but if all he's got to show are dreams people are just going to think he's skyggn, especially so if there are other skyggn people in the family line.
We know Icelandic mages are largely female so I'm assuming a talented male mage can go unnoticed simply because it's not something people keep an eye out for in a boy. If Reynir had sisters and they showed similar talent they'd be far likelier to be taken seriously in the after-Rash world.
