I'm pretty sure this is the family in the census; i have the birth records for the three boys and the ages align. I'm fairly certain Nils is dead just trying to piece together whether that's his death record in the notes above or not, it would make him a pretty old man for the family given all three boys would have been less than 10 when that Niels died at the age of 68. The military connection is interesting and that's what i've been trying to link together.
I think your Niels Larsen was probably married twice. Here is a marriage record for Niels Larssøn Position: Soldat Unge Karl Bryni and Anne Christensdatter in 1777.