Documentation is needed, but on the basis of these census and marriage records it looks like Pearl's parents were William J. "James" Biggs and Mary Ellen Estes of Davidson Co TN, and her grandparents William H. Biggs and Rebecca Ann Crafton of Robertson and Davidson Cos TN. If Pearl and her husband John W. Biggs were indeed first cousins, John's father would appear to have been James' brother John A. Biggs, b ca 1856-1858.
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WILLIAM Biggs married Rebecca Ann Crafton 23 Apr 1856 Robertson Co TN (borders Davidson Co).

1860 CENSUS, Davidson Co TN
Nashville, Ward 8, 4 Jun 1860, p 19 (478)

W. H. BIGGS 27 TN laborer
Rebecca A. 25 IL
John A. 3 TN
William A. 1 TN
(William's middle initial on this census should probably have been listed as J for James.)
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1870 CENSUS, Davidson Co TN

WM. BIGGS 36 TN painter
Rebecca 35 IL
John A. (Jno. A.) 14 TN
Willie J. 12 TN
Mary E. 8 TN
Melissa 4 TN
Simpson 4 months TN
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W. J. BIGGS married Mary Ellen Estes 14 Jul 1878 Davidson Co TN. This couple might be Pearl's parents.

1880 CENSUS, Davidson Co TN
Nashville, ED 47, Page 33, 9 Jun 1880

JAMES Biggs 21 TN TN IL
Mary 22 wife TN TN TN
Ernest 1 son (b June) TN TN TN
REBECCA Biggs 44 mother IL NC NC
Mary E. 17 sister TN TN IL
Malissa 14 sister TN TN IL
Jessie 8 sister TN TN IL
+ two boarders DOUGLAS? and McCORMACK, both RR brakemen
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http://www.tngenweb.org/bedford/Obituaries/Obituary_Index_19...
See obit notice of Carrie Leftwich Biggs, wife of Dr. Ernest R. Biggs, at the above web site, and the WorldConnect Project submission on Ernest and Carrie.
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1900 CENSUS, DICKSON CO TN (borders Cheatham, which borders Davidson and Robertson).

W. J. BIGGS, b Sep 1858 TN TN TN, iron moulder. Married 21 years.
M. E. wife, b 1858 GA GA GA. Married 21 yrs, mother of 6 children, 3 living.
Pearl E., daughter, b 1885 Jan'y? [for January] TN TN GA
M. E., daughter, b Oct 1888 TN TN GA
W. H. BIGGS, father-in-law, b July 1831, 68, TN TN WV
(Relationship should evidently have been entered as "father".)
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1880 CENSUS, DICKSON CO TN

This might be the household of "John A. Biggs", brother of William "James" Biggs. John's son William might be Pearl's husband, John W. Biggs, b 1876. Did not find a marriage for John Biggs to a Jane, but one John A. Biggs married Amanda E. Pitt in Robertson Co TN on 4 Jul 1875.

JOHN Biggs 25 TN TN TN farmer
Jane 26 TN TN TN
William 3 TN TN TN
Laura 1 TN TN TN
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