Who is this Sarah Long?

DE Death Certificate 183
Sarah E. Long, widow, no former spouse listed.  Birth:20 Sep 1839
Death:7 Nov 1931  Age at Death: 91  Residence: Sussex, Delaware
Father: Lettie (yes, that is what it says);  Mother:Suffa Murray
Informant is Parker Long (on 1870 census son of Stephen Lewis Long and Sarah.
Stephen Lewis was son of Benjamin2 Long whose Bible listing his children I own.
n.b., is "Lettie" really Lettie or is it Liddie, sometimes a nickname for Lydia?

There were 3 Sarah Longs about the same age. 
1. The first I think we can eliminate as the one on the DC.  She was a child of
Benjamin Long2 & Elizabeth "Betsy" Ake: 2nd child listed in his Bible b 27 June 
1830. On the 1850 census she is not in Benjamin2's hh388 so she had either died 
or married.

2. A second Sarah Long was the wife of Stephen Lewis Long(3rd child listed in
 Benjamin Long's Bible, b 23 Nov 1832). 
DE Marriage record on Ancestry.com: m 18 Oct 1860 in Sussex. (The m record is 
just a list of marriages and gives no additional information.)
This Sarah is believed to be dau of Elisha Long (of Zeno Sr. of Benj.1)
& LYDIA(nee LONG). 
The 1850 census lists in  hh414 of Elish & Lydia:  Sarah age 11( b 1839)
She was the sister of Zeno Pattey b 1835, Louisa b 1838 and Eber b 1842. 
[Elisha had a sister named Lettie (of Zeno Sr.) which is the 
name given for the father of Sarah on the DC.] 
The 1870 census lists children of Stephen L Long 37 & Sarah Long 30  as: 
Martimore Long 9, Parker J Long 7, Elizabeth Long 5, Eber Long 3, and 
Lecty P Long 1. 
1800 and 1900 find Sarah with Stephen Lewis Long; he died in 1907. 
1910-1830 she is Sarah E with dau Lecta in the hh. 

She seems to fit the DC until mother SUFFA MURRAY is considered.

3. There is another Sarah Long b abt 1830 thought to be the dau of Eber Long 
(of Benjamin1) d 1848 and SOPHIA MURRAY(of David). This Sarah m Thomas Stevens
1 Nov 1849 (Ancestry has marriage date and an earlier bond co-signed by Isaiah 
Long (probably Isaiah of Zeno1, brother of Elisha.)
In the 1850 census Sarah & Thomas with Joseph age 1 are in hh of SOPHIA MURRAY. 
In 1860 they have their own hh and 4 children: William 10, Curtis 8, Joshua 6,  
John M 4; Joseph must have died. 
In 1870 neither Thomas nor Sarah are found but all their children, with the 
addition of Sarah  age 8 and 1yr old Vicy, are in the hh of George Harrison and 
his wife Rhoda (nee Long of Joe of Benj.2). Sarah and Rhoda were cousins. From 
this I assume that both Thomas and Sarah d bet 1868-1870.

So why is Suffa (Sophia) Murray listed as the mother of the Sarah Long d 1931? 
by her son Parker? Is it possible that he did not know which female Long was 
his grandmother? And what is meant by Lettie as the father of Sarah?  Perhaps 
that information was supplied by undertaker?

The DC seems to me to be for Sarah Long m Stephen Lewis Long whose parents 
were Elisha and Lydia Long.

But am I missing something here?