Thanks, Yvonne,
You are correct about the birth years for the two people. I have already done extensive research on this Erik Persson. The 1757-04-22 death record for his wife lists her as "Erik Persson's wife Karin Månsdotter." The date of her death coincides with what the Kånna Arvidsgården tax records show. Erik's wife was old and sick in the 2 years prior to her death and then in 1758 Erik Persson is listed there as a widower.
1757 death record for Karen Månsdotter, Kånna Arvidsgårdenhttps://app.arkivdigital.se/volume/v30538?image=85Kånna (G) C:1 (1743-1815) Image 85 / Page 161 (AID: v30538.b85.s161, NAD: SE/VALA/00202)
1756 tax record for Erik Persson - wife not taxed she is old and sickhttps://app.arkivdigital.se/volume/v840187?image=3510&page=687Mantalslängder 1642-1820 Kronobergs län 1642-1820 (G) 63 (1756) Image 3510 / Page 689 (AID: v840187.b3510.s689, NAD: SE/RA/5520306)
1757 tax record for Erik Persson - wife not taxed, she is sick https://app.arkivdigital.se/volume/v840188?image=3480&page=673Mantalslängder 1642-1820 Kronobergs län 1642-1820 (G) 64 (1757) Image 3480 / Page 675 (AID: v840188.b3480.s675, NAD: SE/RA/5520306)
1758 tax record for Widower Erik Prsson, Kånna Arvidsgårdenhttps://app.arkivdigital.se/volume/v840189a?image=3600&page=705Mantalslängder 1642-1820 Kronobergs län 1642-1820 (G) 65 (1758) Image 3600 / Page 705 (AID: v840189a.b3600.s705, NAD: SE/RA/5520306)
Wife, Karin Månsdotter, Arvidsgården, is listed a baptismal witness for a Kirstin in 1743-08-05https://app.arkivdigital.se/volume/v30538?image=6Kånna (G) C:1 (1743-1815) Image 6 / Page 3 (AID: v30538.b6.s3, NAD: SE/VALA/00202)
All of these things seem to indicate that Erik Persson and Erik Törnqvist are the same person; the tax records/birth records for both 1750 and 1755, show Erik with different last names for same years and living in the same place. This seems to be the most conclusive evidence (yet circumstantial, I realize) that I've found so far - mainly because these records relate specifically to Erik himself.
I am very interested whether you concur and also am curious how you document ancestors for which you never can find "absolute" proof but for which there is so much circumstantial evidence. I would like to preserve this information in order to help a future researcher go further as more information become available through court records or other documents that are beyond my skill level.
Thanks for your help,
Vicki