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

Eliza CARD Birth: 30 Jun 1858, New Bedford, Bristol, Massachusetts Father: William CARD; Mother: Helen M. BYINGTON Marriage: 21 Oct 1879, Bristol, Massachusetts Spouse: Joseph A. STROUP Source: patron submission

Unless this was a "shotgun" wedding, the marriage date appears to be their first child's birthdate.  It's also extremely unlikely they were married in Massachusetts as STROUPs in MA are extremely rare (nor is there a Joseph STROUP in the 1870 census of MA).

2.  LDS.  Family Search: Census Records: 1880 United States (online at FamilySearch.org):  can't find.  Eliza's parents are in Butler Co., PA.

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

4a.  1900 Census Index/Images (online at Genealogy.com; Image #26 of 34 — Orlo was mis-indexed "Otto"):  Howe Twp., Forest Co., PA, p. 57B, SN 13, SD 14, ED 49, enumerated 23 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

11

12

13

14

15

19

20

21

22

23

24

25

27

241

243

Green Eliza O

Head

W

F

Jun 1858

41

Wd

4

4

NY

MA

NY

Boarding Home

0

Y

Y

Y

R

H

Stroup Orlo C

Son

W

M

Oct 1879

20

S

PA

PA

NY

Day Labor

0

Y

Y

Y

Stroup William H

Son

W

M

Sep 1881

18

S

PA

PA

NY

Day Labor

0

Y

Y

Y

______ Hellen N

Dau

W

F

Jun 1885

14

S

NY

PA

NY

At School

6

2

Y

Y

Y

______ Myra C

Dau

W

F

Jan 1887

13

S

PA

PA

NY

At School

4

8

Y

Y

Y

Was Hellen really born in NY?

4b.  1900 Census Index/Images (online at Genealogy.com; Image #25 of 34 — Myra is mis-indexed as "Myra R."):  Howe Twp., Forest Co., PA, p. 57A, SN 13, SD 14, ED 49, enumerated 22 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	11	12	13	14	15	19	20	22	23	24	25	26	27
236	238	Card Charles C	Head	W	M	Mar 1867	33	*			PA	MA	NY	Day Labor Oil ???	0	Y	Y	Y	O	F	H
		____ Hellen M	Mother	W	F	Aug 1835	64	Wd	3	3	NY	VT	NY			Y	Y	Y
		Stroup Myra C	Niece	W	F	Jan 1887	13	S			PA	NY	unk				Y	Y

*Just a blob.  Myra managed to get enumerated twice.