Christian did have a daughter Anna Maria b. 1774, but no other information is known abt her.Matthias' daughter by the same name married John Brinser.His daughter Anna married Peter Kreitzer.In checking the index of my database I don't have a Thomas Seslor.However, I do tie into the Sesslers through Mary Gish (1816-1886)m. David Magnus.Their daughter married Mark E. Sessler (1859-1934).
The only other Anna Nancy Gish that I know of was John G.'s daughter and she was born in the 1780's and married Felix O'neal.
The only other possibility is that perhaps Sessler wasn't her first marriage and she is only recorded under the first marriage.
I checked my database the daughter that married Kreitzer died (1837-1816).She had 10 children - none identified.Anna Maria (Gish) Brinser was born on October 25, 1757 and died in 1846.She is not listed as having any children.
I know this doesn't help much and may make you more frustrated than anything else.