What do the observations of Schultz and d'Arrest have to say? Schultz's positions for all three objects – not just one as the NGC credits – precessed from the published equinox of 1865.0, agree to within two or three arcsec in all three cases with modern data from GSC. These pin down the three objects and show that NGC 91 is a star (Bigourdan also called the same star NGC 91 in his Observations). D'Arrest's positions are not quite as good, but fall within 20 arcsec of the galaxies. His descriptions of the locations and magnitudes of the nearby stars are also good, and confirm the identifications.
So, NGC 90 should be credited to Lord Rosse, Schultz, and d'Arrest (rather than just Lord Rosse and Schultz), NGC 91 to Schultz alone (Lord Rosse and d'Arrest never commented on this star), and NGC 93 again to all three observers. To the description for NGC 90 should be added "* 13 sp."
There are several other identification problems in the NGC 80/83 Group, too. See NGC 81, 82, and 84, as well as IC 1547.