I think I may be able to help you with some of the early history. I have only just discovered this connection to my family, so I am just starting, but I'll tell you what I have.
First off, I am descendant of Agatha Haffner's older sister, Odelia (many spellings of that name). She married Mathias Pfeiffer, a fellow Alsatian, and in 1840, both she, Mathias and her siblings immigrated to Thompson Township, Seneca County, Ohio. These are the Haffners who came over:
1. Odelia (Haffner) Pfeiffer, born 1812
2. Catherine Haffner, born c.1817
3. Joseph Haffner, born c.1820
4. Elisabeth Haffner, born c.1825
5. Agatha Haffner, born 1827
I have not been able to find anything about the other three Haffners. However, I do know that the ties between the Pifher family (the Pfeiffer name was changed) and the Bogner family remained strong at least into the 1920s and 1930s.
I have accumulated A LOT of information on the Bogner line but have not been able to go through it all. Two websites will be of particular interest to you. The first is "The Pitzen Place", set up by someone who I believe is a collateral relative of the Bogners (not sure how). That site is at:http://freepages.genealogy.rootsweb.com/~dpitzen/
The other site is "The American Gase Family Tree", which was set up by similar collateral relatives, which has a lot more early data, it seems. There is where I found the name of the town in Alsace the Anton Bogner came from. It is called Siegen. That site is at:http://www.gase.nl/GedPage/surnames.html
Anton and Agatha Bogner are buried in St. Michael's Catholic Cemetery in Thompson Township, Seneca County. The name of the place this cemetery is at varies. It has been called Frank, Frenchtown, Thompson, and Marywood. The cemetery, however, is there. I have seen it, but did not know at the time to look for the Bogners. A database of names at that cemetery can be found here:http://freepages.genealogy.rootsweb.com/~ohio/seneca/st_mich...
I have yet to go through the info on these sites in much depth myself yet. However, if you'd like to share any more info you might have on the Haffners and Bogners, I'd love to hear it, and I'd be happy to offer info on the Pifher (formerly Pfeiffer) family. They moved in 1852/3 to Crawford County, Ohio.
Would love to hear back from you!