I found the name of another one of my great-grandmother Aase's siblings. According to our family, she had 11 or 12 siblings, and I might have the names of all of them now. Since my newly-discovered great-great-aunt died quite recently and may have living children, I will not post her details here. This actually is quite a big discovery, even though it's not related to my direct ancestry. Ever since I started doing genealogy, I've considered it a mission to find out the names and stories of all of Aase's siblings and "bring them together" again, since many of them were displaced as children and did not know each other growing up.
I found the death record of my 8th great-grandmother, Marthe Cornelisdatter. To be sure, it was not difficult to find, but this is the first time I've had a look. Marthe died in 1727 in Vanse parish, Vest-Agder, at the age of 82 (meaning she was born in 1645). She was the wife of Søren Jensen Floss, a tailor from Denmark, and I believe it is likely that Marthe was also of foreign origin - more specifically, I believe she came from somewhere in the Dutch-speaking world. The name Corneli(u)s was first brought to southern Norway by Dutchmen in the 1600s, a period known in Norway as the "Era of the Dutchmen" (Hollendertida). Since nobody by the name of Corneli(u)s is recorded in Vanse in the census of 1664, Marthe was almost certainly not local. We also know that Marthe and Søren had a son, Kornelius Sørensen, who emigrated to the Netherlands and became a tailor in the town of Zierikzee, which might mean that Marthe had roots in that area. (She also had a son who emigrated to Copenhagen).
It might even be Marthe who is the source of our West African DNA, since the Dutch were active in the Triangular Trade and had colonies in the Caribbean. Marthe is the direct ancestor of Daniel Davidsen, my 3rd great-grandfather who had West African admixture. She might not have come from the Netherlands itself, but from one of its colonies. Unfortunately, I haven't found any documentary evidence supporting this hypothesis yet.