I"m not entirely sure if Scanlan had an exit (pardon the pun) strategy other than holding Umbrasyl in place while the others killed him. the Matron said that Vax was meant to shepherd the souls "in a sense". In reality, the job is to guard against people taking advantage of the soul during the moment of transition, since it is a powerful resource, and to exact the Matron's vengeance on those who would try.
Is the Matron of Ravens spiritual? Yes, but also quite physical. Both. The gods are beings from a place outside of reality - with 1 or 2 exceptions. They became 'real' when they fled their home and/or maybe they created this particular reality - it's unclear. They do have bodies. They also created various planes of existence, including their own home dimensions which serve as the various afterlife dimensions. They used to physically war with each other on the planet before it got so bad that mortals tried to kill them. So they created the Divine Gate, a metaphysical barrier to keep themselves away. Now the gods have to communicate via visions. Also the Matron of Ravens is unique among the gods in that she's the only one who used to be mortal and ascended to godhood. She either killed the previous death god and took his domain, or she took his domain and it killed him - or more like deleted him from existence. She did it because she's adamantly opposed to undeath and the last death god liked to create undead slave armies. She's all about that cycle.
