Here is the status of characters from my playthough of all DLC:

1 - Greece
* Deimos is alive, no longer baddie Deimos, an ally sibling who works on the Adrestia and has dinner with Myrrine
* First blade baddies (Hunter, etc.) all dead, never see them again
* My spouse dead, no way to save them, never see them again in Underworld Elysium.
* Brasidas and Phoebe die, no way to save them in Greece. Can save them in Underworld with careful choices.

2 - Elysium
* Leonidas is alive and fishing. No need to kill him. He suggests an alternate plan, to bring the spy alive but stunned to Persephone
* Elpenor, Monger, Octopus - Tartarus, the "hell" of the Underworld
* Persephone is still running Elysium when I last saw her going into the big pit in her temple. In Atlantis, records show the other Isu think she's a psycho
* Hekate - given a spell that makes her tell the truth, no longer Persephone's friend.
* Hermes - alive
* Adonis - banished with no facial disfigurement

3 - Underworld
* Brasidas was here due to a serious error in judgement but was convinced (by me) that he wasn't at fault, war was at fault, so he deserves to go to Elysium
* Hades - defeated in battle by me, stays in the Underworld. Atlantean Isu also consider him to be mentally unstable.
* Phoebe - was here, now with parents in Elysium after some help from me

4 - Atlantis
* Shut down by me with the help of Poseidon. Wild adventure before that and well worth popping the cost of the DLC, IMHO.