I'm not sure if there's going to be a "Secrets of the SSR" to go along with the excellent "Secrets of SHIELD," (EDIT: I JUST HAD TO WAIT A FEW MORE SECONDS!) so I'm putting these here. Do not go any further if you do not wish to be spoiled for the first two episodes of Marvel's Agent Carter.
First up: the big bad Leviathan is the Soviet equivalent of HYDRA. They were first introduced in Secret Warriors, the same comic book that included Daniel Whitehall and Daisy Johnson. It looks like the EPs of Agent Carter and Agents of SHIELD are both fans of the comic by Jonathan Hickman, Brian Michael Bendis, and Stefano Caselli. Like Whitehall, it appears that the MCU Leviathan is markedly different from their comic book counterpart.
The Leviathan turncoat is named Leet Brannis, a very obscure villain that fought the Whizzer (you may laugh, yes) and only appeared in All Winners #4.
Roger Dooley was an agent of SHIELD who was super sexist and corrupt — he once made She-Hulk go through a strip search. It looks like his MCU counterpart is slightly better, as well as having been moved backwards in time (the same goes for Edwin Jarvis).
Aside from Howard Stark and Anton Vanko, all other names appear to be original. There certainly don't appear to be any characters by the name of Daniel Sousa, Jack Thompson, Ray Krzeminski, or Angie Martinella.
The best line of the night, however, belongs to Angie as she explains that one of the girls at the boarding house works for Goodman, Lieber, Kurtzberg, and Holliway, which is not only the law firm that She-Hulk used to work for, but also incorporates three names of Marvel creators (Martin Goodman [publisher], Stanley "Stan Lee" Lieber, and Jacob "Jack Kirby" Kurtzberg).
Comment if you notice any ones I missed!