1a.  Jordan R. Dodd, ed.  1998.  Marriage Index: Ohio, 1851-1900.  Liahona Research, Orem, UT (Broderbund CD-236):

Keiser, G.W.	Duffee, Hettie W.	5 Dec 1870	Richland Co.
Stroup, Daniel	Keiger, Hattie	1 Oct 1871	Richland Co.

The 1870 marriage record would be a stretch because "Hettie" (the nickname for Esther) isn't "Hattie" (the nickname for Harriet), but "Keiger" could be a mis-reading of "Keizer," which is a phonetic spelling variation of Keiser/Keyser/Kaiser/Kiser/etc.  But the real hangup is that "Duffee" isn't "Dorrance."  On the other hand, the time and place are right on.

1b.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Daniel STRAUB Spouse: Mary J. PARROTT Marriage: 19 Sep 1885, Richland, Ohio Source: Marriage Records, 1813-1930. Ohio. Probate Court (Richland County)

2a.  1870 Census Index/Images (online at Genealogy.com):  Daniel is unmarried and living with his parents in Mansfield (Ward 4), Richland Co., OH.

2b.  1870 Census Index/Images (online at Genealogy.com, Image #50 of 72):  Shelby P.O., Shelby Village, Sharon Twp., Richland Co., OH, Roll 1261 (Book 1), p. 318B, PN 24, 207/206, enumerated 21 Jun 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Keiser George W

21

M

W

Dentist

Ohio

Living in hotel.

3.  1880 Census (indexed at FamilySearch.org; page image online at Ancestry.com, Image #31 of 54):  94 Water Street, Mansfield, [Madison Twp.,] Richland Co., OH, Roll 1062 (Book 1), p. 373C, PN 31, SD 6, ED 223, enumerated 8 Jun 1880, official enumeration date 1 Jun 1880 (extracted by Diana Gale Matthiesen):¤•

1880:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

8

9

10

11

13

21

23

24

25

26

*

94

254

290

Straub, Cecilia

W

F

69

/

/

Keeping House

Bavaria

Bavaria

Bavaria

94

254

291

Straub, Daniel

W

M

39

/

Laborer

Bavaria

Bavaria

Bavaria

______, Hattie

W

F

25

Wife

/

Laundress

Ohio

Virginia

Ohio

______, Edward

W

M

8

Son

/

/

Ohio

Bavaria

Ohio

______, Cecilia

W

F

7

Dau

/

/

Ohio

Bavaria

Ohio

______, Josephine

W

F

4

Dau

/

Ohio

Bavaria

Ohio

Dorrance? Josephine

W

F

31

Sister in law

/

Domestic servant

/

Ohio

Virginia

Ohio

*Water Street

If Josephine and Hattie are sisters, as their birthplaces support, then they should have the same surname.  So who had a prior marriage, Josephine or Hattie?  The census indicates in Column 9 that Josephine is "single" (i.e., not married, widowed, or divorced), so it must be Hattie, which means her age has to be way off because she's not really old enough to have married Daniel, much less to have had a prior husband — and I'll wager she was closer to 35, than she was to 25.

3.  1890 Census:  the 1890 Census Population Schedules were destroyed.

4.  1900 Census Index/Images (online at Genealogy.com, Image #31 of 44):  129 South Adams [St./Ave.], Mansfield City (Ward 9), Madison Twp., Richland Co., OH, Roll 1317 (Book 1), p. 16A, SN 16, SD 13, ED 126, enumerated 13 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):¤•

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

*

129

314

387

Straub Daniel

Head

W

M

May 1842

58

M

19

Ger

Ger

Ger

1845

54

Na

General Labor

?

Y

N

Y

O

F

H

______ Mary

Wife

W

F

Jun 1859

40

M

19

4

4

OH

Y

Y

Y

______ Betie?

Dau

W

F

Jun 1883

16

S

OH

Ger

OH

Y

Y

Y

______ Henry

Son

W

M

Feb 18??

7

S

OH

Ger

OH

at School

9

Y

Y

Y

______ Viola

Dau

W

F

Aug 1893

6

S

OH

Ger

OH

at School

9

Y

Y

*South Adams

Daniel and Mary were married in 1885.  If Viola really was born in Aug 1893 (which would make her 6 years old in June), then Henry cannot be seven years old and be born in February.