guess I'm not a great help here. Especially not with the O'Brien part of the family. Have you ever traced back the first (immigrant) generation to where they had come from? Only finding the name of their (birth) town or location where they had lived can give you more facts to work for their earlier family history.
I've just had a look at the Ellis Island database (EIDB; they didn't arrive there, I know) - just to look at the names and their origins. There were people named Naftelberg, at least 6 of them from Czernowitz, back then in East-Galicia, Austria and today Ukraine as I believe. That name anyway sounds pretty similar, and might be a valid spelling variant
I've also read some of you earlier posts and found that my (guessed at) Naftali <> Neftelberg connection did actually exist. Looks like an attempt at keeping the original name as part of the new one back then. This also brings Neftelberger still closer to Naftelberger which I've found in the EIDB.
The only suggestion that comes to my mind is - IF your people actually have come from there, you might try and post to the boards for Galicia: http://boards.ancestry.com/mbexec/board/rw/localities.ceeuro...
There are also several websites with more information and search aids for that specific region: Galicia, Bukovina, Chernivtsi, Czernowitz). For instance here http://czernowitz.ehpes.com/