Apparently the search engines were not happy with the results and so decided to go back to New Orleans overnight and shovel up some more bones for us. First, I have no idea who Alice Vogel or Fitz was. But, two birth records surfaced: Marie Virginie Vogel, born 02/06/1851, Female White, Father William, Mother Armide Fitz; Marie Christina Louise Vogel, born 05/12/1853, Female White, Father William, Mother Ulalie Armide Fitz (that's right, Ulalie!!?). So, we know Fitz was a maiden name which should explain the involvement of Charles Fitz as a likely blood relative of Armide. There is also a Friedrich Vogel who has a son (same name) on 08/04/1851 with a Christine Preine (also noted as Pruenne in marriage records for 2/15/1850). Possibly related but not clear.
Now, William is actually George Charles William Vogel, but is not usually listed by full name. A bit insanely, Livingston's Law Register: (for 1854) [by John Livingston, at 157 Broadway NY] has under Foreign Consuls in Other Cities relating to both Hamburg and Oldenburg one William Vogel in New Orleans on page 278. Much worse, page 279 has Wilhelm Vogel in New Orleans for Prussia. All very confusing, and most likely misleading. And I'm not so sure we can say William Vogel actually died after going missing...there are two marriage records in the name of Charles Vogel in New Orleans afterwards, and there's a rather short list of Vogels getting hitched in that town around then. Did I leave anyone out?