There are Italian surnames that begin with "SB". You can go to the Steve Morse search form for Ellis Island and only enter "SB" as a partial name and a multitude of names will appear. Bear in mind that the surname may have been misspelled when the transcription took place.http://stevemorse.org/
I have searched on the surnames you list and I cannot find them in Italy today. However, I have found similar names in the Ellis Island Database. These ae "Sbacchi" and "Sbocchi". When viewing the Italian White Pages telephone directory, the name Sbacchi appears in Palermo. Since you have found the family in the 1900 US census, you know that they arrived in the US prior to that date. The unfortunate part is that the manifests do not reveal too much information in this time period. However, the census records usually indicate the year the person immigrated, so that is a plus. Have you looked at the later censuses?
Perhaps this web site will be of interest to you, since it covers a lot of information about records and surnames in Termini:http://www.termini-imerese.org/home.htm
If you are a member of Ancestry.com, you can check to see if they have posted the civil registration records for Termini. I have check the familysearch.org site (Mormons) and they do not show it on-line yet. New records are added periodically, so keep checking it. If you wanted to rent and read the civil registration microfilm records for Termini Imerese (Palermo), they are available for the period 1820 - 1910, at a Mormon Family History library.