I am having a hard time with Swedish records.

Looking for information regarding the following persons using their names after they came to America. My guess is names were changed slightly after immigrating.

Anna Marie Hanson born 1 January 1855 (+/-) in Sweden
died 23 Novmeber 1946 in Minnesota, USA
Her parents Lars Hanson and Betty
Immigrated to USA in 1868

Lars Erickson born 2 April 1843 in Sweden, died 1909 in Minnesota
His father Erick Larson

Peter Tilberg born 1852 in Sweden, died 26 october 1933 in Minnesota, USA
Immigrated to USA in 1883

Any help would be greatly appreciated. Thank you.