I've stumbled upon this forum by a compelete accident,
I've been attempting these researches several times now and didn't come upon anything big.
I don't know if the family you're talking about is jewish or not because the names are confusing (sarah, david, fannie...) so I'll just give the info I have.
I'm from a jewish family that migrated to Russia from somewhere in Ostro-Hungary, I have information from about 3 generations back so I can't trace it to the 1700's, but it is possible.
In the middle of the 1800's it was a very vast family with about a dozen children, many were lost during WWII and we don't know what happened to them, probobly most of them died.
A few of the children that lived through it migrated to Israel and now the whole family is here.
There are about 30 people who are direct himmelreich descendants.
Hope this helps, hope to get a reply.