First of all Jacob Huhner died long before 1920. I found Eva in all the census records from 1880 to 1920 as a widow. Jacob appears with the family in the 1860 and 1870 censuses. BTW the surname is spelled Hughner in 1860, Huckner in 1870 and again Hughner in 1880. I think the enumerator may have misspelled the surname in the 1850 census see Jacob Humer (if you look at the mother's surname it looks like it could be Huhner).
Some researchers on Ancestry have Eva's parents as Jacob Bauer 1811-1861 and Anna Maria Graeser 1810-1887 both of Mussbach, Germany and who settled in St Clair County, IL. They arrived in New Orleans aboard the Michigan in 1847. They had a daughter Eva born ca 1838 and she appears with them on the ships list and the 1850 census.
Of course this does not match the records claiming Eva was born in Alsace and the census record in which she claimed to have immigrated in 1854. It would also seem strange that this Eva would marry a man from New Orleans while living in Illinois. Of course they still could be the same person, but I suggest not assuming they were.
I suggest getting Eva's death certificate which should list her parents' names. I strongly recommend getting her obituary which may list her parents, any surviving siblings and possibly the town she was born in. If you know what cemetery she is buried in (which should be on the death certificate) I suggest finding out what they have on her in the records and what is on the tombstone (an exact birth date is important). If you know what church she was a member check to see what they have on her in their records.
One way to prove or disprove her connection to the Bauer's of Illinois would be to look at the estate records for Jacob and Anna Maria.