your list shows for the first time (?) BAVARIA as the origin for some of your people. At the EIDB site there are also (although a bit later) at least two people from Bavaria with the surname Nectelberger
0127. Nectelberger, Heuir M 16y Bavaria
0128. Nectelberger, Louis M 13y Bavaria
arriving from Hamburg via Southampton on Sep 01, 1893.
This could be a further (mis-spelled) name variant.
Another link that comes to my mind, if you haven't tried it already: http://www.surnamenavigator.org/
Wish you all the luck