Investigating the names in the Raritan Reformed Church Membership Roll

I found the church membership roll in the pamphlets for the celebrations of the 145th and 150th anniversaries of the Raritan Reformed Church (Raritan, Illinois; see previous post, Simonson Genealogist: Raritan Reformed Church in Raritan, Illinois).

Although Mrs. Simon V.A. Simonson is listed as a charter member, Mr. Simon V.A. Simonson is not, which I find interesting.  Their firstborn son, Dennis Nevius Simonson (1855-1930) was the first child baptized in the church, and it appears from these membership records that other children including Mattie Louise Simonson (1870-) and possibly Gertrude Ellen Simonson (1859-) and Alice Wortman Simonson (1874-) were also members of the church.  

There are actually two Gertrudes listed: Gertrude Simonson Cortelyou and Mrs. Gertrud[e] E. Simonson Rankin.  According to new.familysearch.org, Gertrude Ellen Simonson (1859-) married Samuel A. Rankin (1859-).  Perhaps then Gertrude Simonson Cortelyou is Gertrude Simonson Rankin's cousin/aunt?  This would make Gertrude Simonson Cortelyou = Gertrude Ellen Simonson (1833-) daughter of Dennis Simonson (1793-1867) and Ellen Nevius (1800-1877).  new.familysearch.org has her listed as married to William P Wright (1829-), however, with no mention of a Cortelyou.  Perhaps this is an unrelated Gertrude Simonson (or branched from the tree farther back in New Jersey, or a second marriage, or new.familysearch.org is wrong)?  Actually, it appears she is the daughter of Garret Simonson and Martha Dunham (see farther down).

Garrett Simonson and Mrs. Martha Dunham Simonson also appear in the 1856 members list.  A search on familysearch.org shows them in the 1880 census.  Garret[t] Simonson was born in 1820 in New Jersey (although the 1860 census says New York), and Martha was born in 1825 in New Jersey.  Martha's mother, Catharina Dunham (1794-; born in New Jersey), also lives with them.  Annie E. Dunham (1826-; born in New Jersey), Martha's sister also lives with them.  An 18 year old Charles Harden lives with them, no relation.  Searching on new.familysearch.org reveals:

1. Garret Simonson (born 9 January 1820, Raritan, Somerset, New Jersey) of Dennis Simonson and Gertrude Cock.  He has a brother named John Simonson (1816-).  Apparently this information can be found on microfilm in the Family History Library in Salt Lake City.
2. Garret P. Simonson (born 1815-1820 in New Jersey) married Martha M. Dunham (1824-).  They had two children, Robert B. D. Simonson (1848-) and Gertrude Ellen Simo[n]son (1853-).

This looked like a safe bet, so I combined the two records on new.familysearch.org.  Apparently R.B.D. Simonson listed as a member in 1872 and one of the Gertrude Ellen Simonsons (new.familysearch.org has her as wife of Abraham Cortelyou) are children of Garret Simonson and Martha Dunham.  Finding another duplicate entry in new.familysearch.org, R.B.D. Simonson = Robert Barkley Dunham Simonson. 

Searching for John Simonson (1816-) turned up a death record on familysearch.org for John Simonson (1816-1889; died in Plainfield, New Jersery; occupation = clergy; widowed at death).  I did a Google search for "plainfield new jersey reformed church simonson" and found this funny little article from September 19, 1891 in the New York Times: http://query.nytimes.com/mem/archive-free/pdf?res=F30F15FB3E5E10738DDDA00994D1405B8185F0D3.  In the article, it says the recently late Rev. J. Simonson was pastor of the Trinity Reformed Church in Plainfield.  It lists John Goldsmith Payntar as his relative.

More likely than not, Garret Simonson (1820-) is a relative of Simon Van Arsdale Simonson, but how, I still do not know.  UPDATE: see Simonson Genealogist: Relationship between Garret Simonson (1819-) and Simon Van Arsdale Simonson (1830-1921).