I found all the info I could possibly find on the first couple you requested, all the way back to Norway, and their origins in Norway, which are in my earlier postings. I hope you've been able to print those out and organize that information.I post is as I find it, and sometimes the info needs to be organized by you. My info also included better spellings for the names.
Here was the first couple you requested: "Seeking info on nels Larson born 1822 in Norway his wife Anna m. Larson born 1839 in Norway they lived in winneshiek, Iowa with their children Martin, Anthony, nels, Andrew,Amelia, Paulina,Holver, ole and Matidy."
Now for the next couple, here is what you wrote: "Their son nels r. Larson born sept. 1865 in Iowa and his wife Martha b. Larson born dec. 1861 in Norway they were married in 1893 and lived in brainerd, minnesota Martha had 5 children before she married Mel they were Besty, Sara, Tina, selvert and olena Olsen they then had more children together named ole, Martin, Fremond, George and Lloyd Larson."
Brainerd is in Crow Wing County, MN
Here is the 1900 census in the Brainerd area.They actually live in Long Lake & Maple Grove Townships, Crow Wing, Minnesota
The 1900 census for this family has three of the older children from the first marriage living with their mother Martha.They have the last name Olsen.
Nels R. Larson and Martha's oldest son Ole was born in MN on Aug. 1893 according to the 1900 census.
It says in 1900 that Martha was born in Dec. 1861, and emigrated in 1868 from Norway.That is good news, because she should be somewhere on the 1865 Norway census online.But her first name could have been changed/Americanized.Martha is a name in Norway, but also Marthe, Marte, and other variations. She must have been confirmed in the USA.Was she in Iowa first?Those church records might help.
The Olsen kids living with the Nelsons in 1900, Tina Olsen, b. Minnesota Aug. 1886, father born in IA, mother born in Norway Severt B. Olsen, b. Minnesota May 1888 Olive (Olena) M. Olsen, b. Minnesota Sept. 1890
The list of Olsen kids you provided: Besty, Sara, Tina, selvert and olena Olsen
So the Olsen father was alive at least in Jan. 1890.
So you have any other information?About the sisters Betsy and Sara?
Did I understand that Martha's maiden name was Larson? (Larsen possibly, in Norway)