I cannot find any evidence to substantiate my theory. However, I present it for discussion.
Conclusion: Floki’s second daughter who was married in the Faroe Islands to a chieftain, was named Guðrún Flókadóttir?
Theory:
Landnámabók - Fyrsti hluti
2. kapituli.
[Flóki sigldi þaðan til Færeyja ok gifti þar dóttur sína. Frá henni var Þrándr í Götu. Þaðan sigldi hann út í haf með hrafna þá þrjá, er hann hafði blótat í Nóregi.]
Flóki sailed from there to the Faroe Islands and married his daughter there. From her was Thråndr i Gata. From there he sailed out to sea with the three ravens he had sworn in Norway.
From Her, BORN from her, was Thråndr i Gata.
From: https://en.wikipedia.org/wiki/Tr%C3%B3ndur_%C3%AD_G%C3%B8tu
Þrándr í Götu - Tróndur í Gøtu (Icelandic: Þrándur í Götu, Old Norse Þrǫ́ndr í Gǫtu) (c. 945 – 1035) was a Viking era chieftain in the Faroe Islands.
Tróndur í Gøtu
Born: 945
Faroe Islands
Died: 1035 (aged 89–90)
Faroe Islands
Parent(s): Torbjørn Gøtuskegg and Guðrún
The Icelandic Færeyinga Saga that was written in 13th century says:
There is a man named Grímur Kamban. Grímur was the first person to settle the Faroe Islands. In the time of Haraldur hárfagri – Fairhair – a large number of people fled in the face of his tyranny. Some settled in the Faroe Islands and dwelt there, while some sought other unpopulated lands. Auður hin djúpauðga sailed out to Iceland and called in at the Faroes and there gave Þorsteinn the Red’s daughter, Ólöf, in marriage, and thence originated the greatest family line of the Faroe Islanders, which they call GataChaps, who lived on Austrey.
There was a man called Þorbjörn. He was known as Gata-Chap. He lived on Austrey in the Faroes. His wife was called Guðrún. They had two sons. The elder was called Þorlákur, and the younger Þrándur, [Tróndur]. They were promising men. Þorlákur was both big and strong; Þrándur was also of the same build when he grew up, but there was a large difference in their ages. Þrándur had red hair and a freckled face, handsome to look at.