The St. Louis County historical society might have obituaries or other information. Here are the three brothers on the Minnesota death index. You can also send for their death certificates for only $9 each at this website.
http://people.mnhs.org/dci/Search.cfm

then search for these:
ERICKSON, ALBERT ARMAS
Date of Birth: 29 Aug 1911
Place of Birth: MINNESOTA
Mother Maiden Name: JARVINEN
certid# 1978-MN-012954
Date of Death: 17 May 1978
County of Death: ST. LOUIS

ERICKSON, ANSEL
Date of Birth: 02 Aug 1906
Place of Birth: MINNESOTA
Mother Maiden Name: JARVINEN
certid# 1978-MN-007117
Date of Death: 04 Mar 1978
County of Death: ST. LOUIS

ERICKSON, ARNOLD ROGERT
Date of Birth: 31 Mar 1902
Place of Birth: MINNESOTA
Mother Maiden Name: JARVINEN
certid# 1961-MN-016787
Date of Death: 23 May 1961
County of Death: ST. LOUIS

The Minnesota birth record shows that Arnold is probably named Arno - a more Finnish name.
You can send for his birth record too:

http://people.mnhs.org/bci/search.cfm

Erickson, Arno Robert
Date of Birth: 31 Mar 1902
Mother Maiden Name: Jarvinen
certid# DC-81915
County of Birth: Wadena

It seems like he is oldest, and born in Wadena County.

1910 census - best match

https://familysearch.org/pal:/MM9.1.1/M2PK-Q8H
name: Arno Erickson
birthplace: Minnesota
relationship to head of household: Son
residence: Hibbing, St Louis, Minnesota
marital status: Single
race : White
gender: Male
immigration year:
father's birthplace: Finland
mother's birthplace: Finland
family number: 36
page number: 3
Household Gender Age Birthplace
self John R Erickson M 48y Finland
wife Sophie Erickson F 40y Finland
son Arvid J Erickson M 14y Minnesota
dau Lydia Erickson F 11y Minnesota
dau Lily Erickson F 9y Minnesota
son Arno Erickson M 8y Minnesota
son Arthur E Erickson M 5y Minnesota
son Anshelm Erickson M 3y Minnesota
self Albert J Meline M 24y Minnesota
wife Millie A Meline F 26y Minnesota
dau Ielean A Meline F y 6m Minnesota
self John E Johnson M 34y Sweden
wife Mary S Johnson F 18y Sweden

The California death index shows that the brother Arthur E. Erickson died in California.
ERICKSON, ARTHUR EVOLD
birth: 07/30/1904
mother's maiden: JARVINEN
Male
birthplace: MINNESOTA
county of death in California: SOLANO
Death Date: 04/08/1987
soc. Sec. Number: 475-05-9381
age: 82 yrs

The Wadena county historical society, and the St. Louis County historical society contact addresses, etc. are on this page:
http://www.mnhs.org/localhistory/mho/chsclo.html

MInnesota Birth Index

Erickson, Robert Arnold
Date of Birth: 05 Dec 1922
Mother Maiden Name: Fitzpatrick
certid# 1922-31503
County of Birth: St. Louis

The 1910 census gives more information on John Erickson and his wife Sophie Jarvinen Erickson.

name: John R Erickson
birthplace: Finland
relationship to head of household: Self
residence: Hibbing, St Louis, Minnesota
marital status: Married
race : White
gender: Male
immigration year: 1888
father's birthplace: Sweden
mother's birthplace: Finland

name: Sophie Erickson
birthplace: Finland
relationship to head of household: Wife
residence: Hibbing, St Louis, Minnesota
marital status: Married
race : White
gender: Female
immigration year: 1890
father's birthplace: Finland
mother's birthplace: Finland

Since all children were born in Minnesota, I would say they met and married here. Wadena county was where Arno was born. So maybe Hibbing came later.

In 1920 this looks like the Erickson family in Hibbing, but the mother Sophie is dead? and a much older wife is there.
https://familysearch.org/pal:/MM9.1.1/MW1J-ZFZ
name: John R Erickson
residence: , St Louis, Minnesota
estimated birth year: 1862
age: 58
birthplace: Finland
relationship to head of household: Self
gender: Male
race: White
marital status: Married
father's birthplace:
mother's birthplace:
film number: 1820860
digital folder number: 4312208
image number: 00333
sheet number: 9
Household Gender Age Birthplace
self John R Erickson M 58y Finland
wife Amalie Erickson F 64y Finland
dau Lydia Erickson F 22y Minnesota
son Arneo Erickson M 17y Minnesota
son Arthur Erickson M 15y Minnesota
son Anshelm Erickson M 13y Minnesota
son Aernas Erickson M 8y Minnesota

Best match on the Minnesota death certificate index:
ERICKSON, SOPHIA
Date of Birth: na
Place of Birth: na
Mother Maiden Name: na
certid# 1918-MN-017035
Date of Death: 22 Oct 1918
County of Death: ST. LOUIS

If you order a copy, it may say where she was born in Finland, her parents, cause of death, etc.

http://people.mnhs.org/dci/Search.cfm