I think it was mentioned Mannheim flunkies are probably named Intergang characters.
I had some wild wild guesses on the museum curator from Secrets too, but the only two that come up are too far fetched. Its easy to find, but I just can't justify them.
By the end of episode 17, 147 characters were supposed to appear, and by the end of episode 18, 150 characters were supposed to appear, so there are only 3 new characters in "Secrets"-Harm, Secret, and Detective Daniels.
Since everyone with a name on the show seems to be a DC character, it wouldn't surprise me if Mannheim's henchmen, Norman is an existing character. By that logic the pilot-girl from "Misplaced" is also likely a DC character-her name was Amber Joyce and there is an existing DC character with that name.
And since some characters identities are counted separately, I think that Jim Lockhart is likely counted separate from Red Torpedo, and that Danette Reilly is separate from Red Inferno, especially since in the mainstream comics they existed as different people. Who knows how many characters this rule applies to?
Another possibility is that Mother-Box and Father-Box are considered characters, since they're from the comics and have minds of their own. There are 12 characters this episode, but since the Super-Cycle technically appeared in episode 9, that was probably considered its first appearance. So if you count the 9 certain people and the Boxs, plus Norman, you get the goal of 12.
As for subtracted characters, besides Catherine Cobert, there was a character design for Merlyn that appeared alongside early character designs for season 1. Why design him if he wasn't originally intended to be used? And you know all the shoutouts that've happened this season: Headmaster, Ibac, and Sabbac? What if their fights were originally going to be shown and they got cut for time?
