Our tadpoles are unique even from other true souls. Ethel and Omeluum give more insight. Omeluum tells you that the magic surrounding the tadpoles is much more powerful and unique. Trying to remove it in any usual way would be very bad for you. Also note: when you or your companions die, the tadpole never emerges.
Also, true resurrection is not easy to come by. 99.9% don't know it and can't do it. Also note: you can die and have Withers resurrect you, but you still have the tadpole. It dies with you and is resurrected with you. Same with Gale's true resurrection scroll.
Where did you get that? The only difference between the tadpoles is, that we are aware of them and the other true souls are not. This is stated in some conversations. The whole game does not adress any other differences, at least i found none.
The journal of halsin and nettie stated that the tadpole of the drow they fought left the corpse. Every tadpole leaves on death. You can kill them even if you are fast enough and they don't slither away.
First i thought the "downed" mechanic was exactly for that, so that we cannot actually die but have a game over after all party members are out of order.
That would have been a neat explanation since when you lose a fight and are incapacitated you will get dragged to moonrise and become true souls....game over. What we have now is ridicoulous guesswork. We would not have needed Withers ingame who ressurrects us for fking 200 gold. Gales Storyline could start with
Incapacitation instead of his death. The save from the fall could have been something special since a fall on the head from high on might destroy the tadpole too, so it was prevented. Way less hassle with explaining if you ask me.