Where did you read these articles indicating it would be easier as a self employed person? Afaik, there is still no such thing as a self employed visa for Iceland. If you read the work visa options on utl, all of them list an employment contract as part of the paperwork requirements.
As for creating an Icelandic company, I know it isn't hard to incorporate an ehf if you are in Iceland, but I'm not sure how it works if you don't have any Icelandic registration yourself. I at least don't know of anyone who moved this way.
Fwiw though, the definition of highly specialized may not be quite what you think. Iceland is a pretty small country that doesn't tend to attract people at the top of the pile in the business world. Your wife may be able to find a company who will hire her. Based on years of experience doing the paperwork for a work visa myself, it isn't too complex or expensive for companies to hire non EEA employees.