St. Albans is a serious misnomer as regards the origin of these passenger lists. At the end of each month, U.S. officers at Canadian seaports and land border ports of entry sent their ship or border lists to the INS Canadian Border District Office in Montreal
Because this comprehensive set of records was compiled at Montreal, they would be better named the "Montreal Lists." But in later years INS moved its Canadian Border District Office from Montreal to St. Albans, Vermont. Thus when INS eventually transferred copies of the records to the National Archives, the records came from St. Albans, and it is from this latter location we derive the unhelpful name "St. Albans Lists." It is unhelpful because too many researchers assume from that name the records only pertain to arrivals across the Vermont/Canada border.
The following is a list of all the ports whose records are archived under the St. Albans lists:http://thegenealogyspot.com/ShipsLists-Online/usa/saint-alba...
For your second question, the immigrant ship was probably never in either place. The largest Canadian Atlantic ports were Quebec and Montreal (summer) and St. John and Halifax (winter). Beginning in 1895, immigrants destined to the United States were subject to the following procedure upon arrival in Canada: U.S. immigrant inspectors at seaports inspected immigrants bound for the United States after they passed Canadian quarantine. If admitted, the inspector issued each passenger a "Certificate of Admission" showing he or she had been inspected and admitted.
Railroads required all passengers who landed in Canada within the last thirty days to present their Certificates of Admission before boarding a U.S.-bound train. Then, when the train stopped at the border, another U.S. inspector boarded the train and collected the Certificates of Admission. It is more than likely that your ancestor entered the United States aboard a train whose first stop in US territory was Buffalo.