I cannot find any information about these three Moser children in the 1870 census:

Census: 17 Aug 1870. Marion Township, Owen, Indiana, United States.^[1]

• Jacob Musser, 38, male, white, farmer, real estate value $1200, personal estate value $250, born Bavaria, father of foreign birth, mother of foreign birth, male citizen 21 or over.
• Elizabeth Musser, 10, female, white, born Ohio, father of foreign birth, mother of foreign birth.
• Mary Musser, 6, female, white, born Ohio, father of foreign birth, mother of foreign birth.
• John Musser, 5, male, white, born Indiana, father of foreign birth, mother of foreign birth.

Please see Jacob Moser for more information about this family.

• 1870 U.S. census, population schedule, Marion Township, Owen, Indiana, p. 7, dwelling 42, family 42, Jacob Moser; digital images, FamilySearch (https://familysearch.org : accessed 21 February 2017); citing National Archives and Records Administration microfilm M593, roll 348.