Yeah it could be fun. The lich is ultimately just sitting and waiting for them cause he is looking to enter a higher plane through some funky magic but is tethered to the material plane because of their soul. He is literally using the party. This may throw a wrench in his plans a bit

Well in Pathfinder there is a pretty clear delineation between psychopomps and the Grim Reaper so I think we are good there. The SoA actually makes it impossible to revive you so I imagine the soul does not take a normal path into the afterlife and instead gets sucked up by the sphere as well

Hmm yeah you have a point

Well the Grim Reaper is a death, but not THE death

Yeah I was thinking that the half that got sucked in are fighting the Grim Reaper on the edge of Limbo while the half that remained are desperately trying to find a way to bring them back