Let's say a player dies, gets revived as their dreamself but their dreamself also dies. Would it be possible for the player to continue the game if one of their corpses were used for the second prototyping of their sprite? Would that sprite be able to go god tier?

They could continue the game as a Sprite, as we’ve seen Sprites survive after the end, but I don’t know if they would count for… Actually yeah they do seem to count, given Jade went God Tier with Jadesprite as her Dreamself, so as long as that Sprite died on the Sacrificial Slab, yeah.