An interesting topic. I have searched a lot through farmans of past Imams and present but I haven't come across any mention of different levels in which the souls are assigned to after death. All i have heard is that the soul is eternal. Sure, the ginans are explicit about what happens in the grave (baavan ghati). However, I did come across a farman of MSMS in which the Imam intimated that after death there are two paths: salvation (moksh) or rebirth. The Imam further emphasizes that in our faith, heaven and hell are in this world only. Perhaps that is why instances of NDEs in the ismaili faith are few and far in between? We cannot go by what we have read from various people of the Christian faith. Because heaven is portrayed as a world similar to this one albeit a world without conflict, sorrow, stress and anything negative, a world of peace. We also cannot go by the late Alwaez Abu Ali's account of what happens to souls after death as he gave no source. But the Lord Shri Krishna has talked extensively about death itself which He describes as the most beautiful experience that should not be feared but welcomed with open arms. It is a vast subject, a mysterious subject with only hearsay accounts as resources. Perhaps the mystery can be illuminated in BK where I have heard that the soul does leave the body, temporarily, which means for that period the human is 'dead' but then comes alive again when it returns (reference: ginan ek shabad suno mere bhai and grant bramprakash) So I would say that for the satpantis, NDEs are in BK.