Richmond family

I found something interesting today. I was working on the family of Lemuel & Lydia (Richmond) Hammond. I know that she's a Richmond, however, had not had much luck finding her parents or family. Living with Lemuel and Lydia in 1860 were twins Arabella and Isabella Richmond. I assume that they are related somehow to Lydia.

Today I found the 1850 census listing for Arabella and Isabella. They are listed as living with Austin and Malina Richmond (who I assume are their parents) along with the rest of the children. Twins born exactly in 1848 with names Arabella and Isabella must be pretty rare, so I am pretty sure this is their family. What is even more convincing is that Arabella married Cephas Parker and they named one of their children Bela, which is one of the sons of Austin and Malina.

What's more interesting is that Arabella and Cephas named their first son Lemuel and their first daughter Lydia, which I can only assume was done in honor of Lemuel & Lydia Hammond. Perhaps they had taken in the girls after their parents had died and raised them.

Richmond family ponderings

Somehow I happened today to fall into a research problem. Who are the parents of Lydia Richmond, who married Lemuel Hammond? What I know:
1) Per pioneer history, her maiden name was Richmond and she was born in Batavia, Genesee County New York in 1811. Her parents were not named;
2) She has a death certificate as "Lydia Harmond", but her parents were listed as unknown;
3) In 1860 twins Isabel & Arabel Richmond, age 12, were living with Lydia and Lemuel. No relationship is given in the 1860 census.
4) on 04 April 1861, Hiram and Adelia Richmond are witnesses to the marriage of Charles Hammond and Aramintha Parker.

Questions:
1) How are Isabel and Arabel related to Lydia?
2) Who were Lydia's parents?
3) How are Hiram & Adelia Richmond related to Lydia?