During Forsaken there's intel that says when the Forsaken dies all those he are will be brought back. He ate Samantha, he says so in Reckoning. We kill the Forsaken in Reckoning. Therefore, if the intel is correct, Samantha should've been ressurected.
The problem is that ressurection seems to be in the form of a child, one representing her two personalities. One representing her regular self and one representing her zombie overlord self. Being the regular child and the zombie one.
In Paradox Junction the EE step to get the chalk has you see a figure made of stone staring at two shadows on the wall. The shadows fade and then the figure turns to ash. I think this represents Samantha's old form disappearing, being replaced by two shadows of herself.
These twins aren't Shadowsmiths, yet control the dark aether at will. They have dark aether magic, help us on every map so far, and take us to Doctor Monty's House at the end of the map, where Samantha used to live after Origins.
Why doesn't she remember the crew, especially Grey? Well I don't know. Maybe her rebirth was more like reincarnation, she is a new person with the same soul (souls?). Or splitting her soul in two scrambled her memories. They remember some stuff. The zombie one remembers the great war and primis in an audio log. Samantha knew about those events.
Maybe at the end of the game the twins will refuse together and revive Samantha for good. If this is true, the Richtofen ending is the canon one for Forsaken. As SAM didn't use Samanthas remaining energy to build a new body, which technically means she would've used the twins if this theory is true.