Tobias Rachor (C) looked at the birth records from Michelfeld and noted that there was a birth record for an Isaac Oppenheimer dated Apr 25, 1830, but no record for Edward in 1831. http://www.landesarchiv-bw.de/plink/?f=4-1224216-404 Check the About section for his comments.
There are other sources for Apr 23, 1830 as Edward's birthday, including his gravestone, a US passport application, and the Oppenheimers from Michelfeld family tree. However, I haven't found any sources yet for the name Isaac.
(Also, I just found a death certificate from Jacksonville, Florida:
https://www.familysearch.org/ark:/61903/3:1:S3HT-6LNC-RGC?cc=159500... )
