It's very common to see studies of Viking beliefs argue that they did develop along parallel lines. I'm personally very skeptical about these arguments (for reasons outlined below), but they're very influential. One of the most influential studies on this currently is Neil Price's The Viking Way (2002/2015), which proposes the idea of a 'circumpolar' religion, that is a set of beliefs and practices that develop in response to the unique environmental conditions of the far north both for the modern Sami and the ancient northern European cultures. Many other scholars of Viking religion have made similar arguments, using modern shamanistic practices (especially those of the Sami) to try to reconstruct Viking beliefs and flesh out our archaeological evidence

The approach where you use a living people group to study a pre-historic one is called 'ethnographic analogy,' and it's common in archaeology. There are good and bad ways to do it. The good way is to use well-understood living cultures to give us broader ideas about how societies can work (so we don't accidentally assume that everyone in the past looked like us). This allows archaeologists to ask new questions of their material, and imagine possibilities that might not have been clear without the broader perspectives gained from the ethnographic analogy. This is very useful. You can also study living cultures that share many practices with the culture obseved in your archaeology - for example, you could read 16th century writings about Aztec culture, and use them to try to reconstruct cultural practices in Mesoamerica in, say, the 11th century. We know the two are related, because one grew out of the other, so this comparison isn't completely specious. But it quickly becomes problematic if not used very carefully, because it's easy to gloss over changes in time by assuming that anything in a culture's past that resembles something in their present must have the same values and meanings. This can be a useful approach, but only if we remember that similarities between past and present don't imply sameness, and as long as we don't allow the similarities that exist to blind us to the differences. The worst kind of analogy is rooted in older assumptions about cultural evolution (that cultures evolve from magic => religion => science), and assumes that 'primitive' people share common characteristics regardless of their unique histories and contexts. The Sami, being a 'primitive' society living near the Vikings' homeland, must have had similar beliefs because all primitive cultures are basically the same, right? This idea isn't taken seriously by anthropologists anymore (though it shows up all the time in hollywood depictions of 'tribal' savages in northern Europe, ie the 13th warrior, and any movie which shows the Picts), but it still lurks behind a lot of the questions and assumptions people make.

You see a bit of each of these approaches with comparisons between the Sami and the Vikings. On the one hand, people like Price argue that the simliar living situation of the Sami and Vikings so far north resulted in shared religious values and beliefs. This is factually problematic (as you've found already), but could be an ok analogy to make if you were just using the Sami to provide ideas for what sorts of things a person living in northern Europe might believe before testing those beliefs against the practices visible in the archaeology. Price tries to do this testing, but ends up relying pretty heavily on the shamanistic beliefs of the Sami to explain the archaeology rather than just give him ideas for how to interpret it - and this is problematic, because it's drifting toward the improper uses of analogies outlined in the previous paragraph.

These approaches are pretty popular, though, and while I've seen some articles voice strong criticism of scholars who use shamanistic religions (especially the Sami) to 'explain' Viking culture, I see more scholars uncritically citing Price et al (the British Museum right now has a display of supposedly 'magical' objects that copies out Price's arguments like facts). I think this is a serious problem that needs more critical discussion.

The actual answer to your question is complicated, precisely because of this tangled use of the Sami to explain Viking beliefs. So much of what we think we know iron age scnadinavian magic and shamanism is based on the comparison of viking and sami cultures that it's hard to make an honest comparison between them without falling into a circular argument. The simplest answer, however, is that the Sami are a modern people whose beliefs and practices have continued to develop and change for the past 1000 years. If they once shared rituals and beliefs with iron age scandinavia, they're definitely their own thing today.