Skilled IL birders have offered up various opinions on it, with 3 feeling like it is a Neo, 2 saying they didn't think so and 2 others intrigued, but non-committal. So it might have to remain as a possible Neo.
However, one commentator did remind me how Neo's tend to stick around an area for an extended stay. Thus, with the long weekend ahead and birders likely to visit Waukegan or the areas adjacent to it, be on the lookout for a small cormorant. If the bird I had reappears, more ID info can be gathered and help bring final clarity to it.