Passenger List: Thov Thoresen & Signe Thovsdatter

Hello again, it has been a few years since my last post. I hope you are all doing well! You all have helped me so much in the past, and I really appreciate it. I have another research rabbit hole I'm going down: I'm looking for the passenger list of my 4x-great-grandfather, Thov Thoresen Undeberg (1813 - ?), and his daughter Signe Thovsdatter Undeberg (1855 - ?). Another daughter of Thov's is my 3x-great-grandmother, Asjer Thovsdatter Underberg (1837 - 1909), and she married Jorgen Knudsen. I had already made a forum post about them a few years ago (/forum/knutson-family/ but now I'm working on her father and her sister's immigration. According to the bygdebok "Fyresdal : gards- og ættesoge. 2", under "Undeberg Gnr.38/13", it says that Thov and Signe emigrated to New York, USA in 1876. It says nothing further for Signe, but it states that Thov returned to Norway and died at Folkestad in Fyresdal in 1908. Here is a link to that page: https://imgur.com/gallery/undeberg-gnr-38-13-7niebuH. Also, here is the link to Thov and Signe's emigration record from Fyresdal: https://media.digitalarkivet.no/en/view/4259/210. They are numbers 9 & 10 under the year 1876, and it states they left Fyresdal in June of 1876, and were bound for America. I have not been able to find their immigration record / passenger list either in New York or in Canada so far. I assumed that Signe likely stayed in America while Thov returned to Norway for some reason. So, I looked for census records in Norway to see if I could find Thov on one of them to try and pinpoint how long he was in America and when he is documented as being back in Norway. In the 1865 Census for Moland, Telemark, Thov is living on the Undeberg farm along with his wife Sigrid Olsdatter (1813 - 1871) and his daughter Signe. Link: https://www.digitalarkivet.no/en/census/person/pf01038147001541. In the 1875 Census for Moland, Thov is still residing on the Undeberg farm, this time with his son Thore Thovsen (1840 - 1894) and still with his daughter Signe. At this point Thov's wife Sigrid had died. This is the last census we find Thov and Signe in before they emigrate. Link: https://www.digitalarkivet.no/en/census/person/pf01052182001906. When looking for census records to see when Thov was back in Norway, I find one candidate in the 1891 Census for Fyresdal living on Momerak farm: Tolv Toreson (1818 - ?), married to Gundvor Kjetilsdatter (1824 - ?). Link: https://www.digitalarkivet.no/en/census/person/pf01052851001528. Here is the same couple in the 1900 Census for Fyresdal living on Folkestad farm: Tolv Toreson born 1818, wife Gunvor Ketilsdotter born 1826. Link: https://www.digitalarkivet.no/en/census/person/pf01037180000921. When looking once again at the bygdebok "Fyresdal : gards- og ættesoge. 2" under "Folkestad Gnr.37/5" we see a Tolv Toreson Valebjørg (1818 - 1908) who married Gunvor Kjetilsdatter Momrak (1824 - 1909) in 1848. Link to that page: https://imgur.com/gallery/folkestad-gnr-37-5-DWQW8ql. I have come to the conclusion that the bygdebok must have made a mistake and mixed up my Thov Thoresen Undeberg (1813 - ?) with this Tolv Toreson Valebjørg (1818 - 1908), and said that they both died in Folkestad in 1908. Here is the link to the burial: https://media.digitalarkivet.no/en/view/1437/178. Note that the record shows Tolv Toresen Folkestad as being 1) married, 2) born in 1818, and 3) born on the Vik farm, which matches with the bygdebok entry for Tolv Toreson Valebjørg. So this Tolv Toresen could not be the right man because he is still married, presumably to Gunvor Kjetilsdatter. So, I believe that given all this information that Thov and Signe likely both stayed in America, and I have not found any information on them since they left Norway. One possible research avenue could be that they may have settled in the same spot as my 3x-great-grandmother Asjer Thovsdatter Undeberg, who immigrated from Fyresdal to America in 1867 and settled in the Fillmore and Houston counties area of Minnesota, and later moved to Polk county MN. Thank you for any help you can provide, or if you draw the same conclusions I did in regards to Thov Thoresen Undeberg staying in America, contrary to what the bygdebok says.