Goofs

Vikings didn't kidnap woman en masse and take them to be their wives. Vikings were fit men, in their prime, who took pride in their appearance, contemporary accounts say the women were more than happy to be taken. And they didn't take ships full of women; there wasn't a huge amount of empty space on ships, and that's a lot of extra mouths to feed, for very little in return, for a group of explorers and colonists.

While it is possible for women to become selkies, it is entirely voluntary, selkies do not take them them. The only taking is the other way round, there are many stories of humans stealing a selkie's pelt to trap them on land.

Referring to "the Danish, vikings to be exact" is a nonsensical thing to say. Vikings were Danish, Swedish, and Norwegian.