1.  Marriage Record:

2.  1900 Census Index/Images (online at Genealogy.com, Image #20 of 39):  Old Lancaster Road, Easttown Twp., Chester Co., PA, Roll 1392 (Book 2), p. 172B, SN 10, SD 2?, ED 66, enumerated 9 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

19

20

22

23

24

25

27

*

209

218

Capp Seth Bunker

Head

W

M

May 1875

25

M

6?/12

PA

PA

PA

Broker

0

Y

Y

Y

R

H

____ Katherina McS?

Wife

W

F

Apr 1880

20

M

6?/12

PA

PA

PA

Y

Y

Y

Williams William

Servant

B

M

May 1846

54

M

5

MD

PA

PA

Cook

0

Y

Y

Y

________ Emma

Servant

B

F

Aug 1863

36

M

5

0

0

MD

MD

MD

Cook

0

Y

Y

Y

*Old Lancaster Road

3.  1910 Census Index/Images (online at Genealogy.com):  not found — in Europe?

4.  1920 Census Index/Images (online at Ancestry.com):  not found — in Europe?

5.  1930 Census Index/Images (online at Ancestry.com):  not found — in Europe?

6.  George Norbury MacKenzie, ed.  1907.  Colonial Families of the United States of America.  Grafton Publishers, New York (reprinted 1966 by Genealogical Publishing Co., Baltimore, MD; OCR'd version online at Ancestry.com).  On pp. 132-137:  a genealogy of Seth Bunker CUPP, our subject, with no mention of his wife or any children. 

7.  Anon.  1950.  The Colonial Society of Pennsylvania: Charter, Constitution, By-Laws, Officers, Members, etc.  (online at GenealogyLibrary.com):

p. 26	Members...
p. 57	CAPP Elected 1915 No. 307 JOHN HOWLAND = ELIZABETH TILLEY. In Plymouth Colony, 1620. John Gorham = Desire Howland. Shubael Gorham = Puella Hussey. Joseph Worth = Lydia Gorham. Benjamin Bunker = Abigail (Worth) Bunker. Timothy Bunker = Dinah Coffin. Thomas Stitt = Ann Bunker. Seth Bunker Stitt = Sarah Wilkinson Wall. William Musser Capp, M.D. = Ida Estella Stitt. SETH BUNKER CAPP SUPPLEMENTALS Tenth in descent from Rev. Stephen Bachiler, in Mass., 1632. Tenth in descent from John Tilley, in Plymouth Colony, 1620. Ninth in descent from Tristram Coffin, in Mass., 1642. Ninth in descent from Ralph Farnum, in Mass., 1635. Ninth in descent from Thomas Gardner, in Mass., 1623. Ninth in descent from William Hayward, in Mass., 1648. Ninth in descent from Christopher Hussey, in Mass., 1632. Ninth in descent from Stephen Kent, in Mass., 1638. Ninth in descent from Thomas King, in Mass., 1635. Ninth in descent from Thomas Look, in Mass., circa 1646. Ninth in descent from Robert Paddock, in Plymouth Colony, 1643. Ninth in descent from John Severance, in Mass., 1636. Ninth in descent from Christopher Smith, in Rhode Island, 1650. Ninth in descent from Thomas Thayer, in Mass., 1645. Eighth in descent from George Aldrich, in Mass., 1631. Eighth in descent from George Bunker, in Mass., before 1658. Eighth in descent from John Gorham, in Mass., 1643. Eighth in descent from Thomas Hatch, in Mass., 1634. Eighth in descent from John Hewes, in Mass., 1632.
p. 58	Eighth in descent from Thomas Macy, in Mass., 1639. Eighth in descent from John Rogers, in Mass., 1643. Eighth in descent from Rev. William Wickenden, in Rhode Island, 1637. Eighth in descent from Lawrence Wilkinson, in Rhode Island, 1647.  Eighth in descent from William Worth, in Mass., 1665.

8.  William Howland, ed.  1939.  The Howlands in America.  The Pilgrim John Howland Society, Detroit, MI (online at HeritageQuest at Genealogy.com):

p. 65	COMPLETE MEMBERSHIP LIST * = Life Members † = Deceased
p. 68	146 *Seth Bunker Capp . . . . Philadelphia, Penn...

9.  P.C. Croll.  1926.  Weiser, Conrad, 1696-: Conrad Weiser and His Memorial Park, a Little History in Three Parts.  Reading Eagle Press, Reading, PA (online at GenealogyLibrary.com):

p. 77	LIST OF CONTRIBUTORS Classified as to Towns...
p. 86	Philadelphia, Pa... Seth B Capp...