First, what would make such a possibility legit? Even an unverifiable proposal that there is a transcendent version of me that prearranges the characteristics of its next material avatar doesn't really fly, if the latter receives neither the enlightened memories of the meta-mind nor the inferior memories of the last avatar. IOW, it wouldn't be an incarnation at all, but just another entity such a "doll-maker" has contributed to.
Without memory continuance, there is no continuance.
If an individual named Jane has no recollection of being John in a past life, then there's no justifiable connection between the two. If she does have memory of him, then all the baggage of what he was and did will still be affecting her and derailing a genuine renewal. And if that information is blurred and ambiguous, then the confusion might generate worse or more traumatic consequences than the explicit knowledge.
Without memory validating continuance of my personal identity in a new body, I might as well claim that the nearest-in-time human fetus that acquires consciousness after my death is a continuation of me -- which will likewise possess zero information about my expired life in its head (as with any other random or not-so-random selection).
The awareness of any developing brain in a womb incrementally arises from blankness -- an absence of everything. That's the universally shared factor or provenance that might worthlessly permit a belief months after the funeral with respect to a surviving family member pointing to a haphazard newborn animal or person and claiming that _X_ is the persistence of someone they lost. But in the context of that qualification, so would any other neonate organism be a spurious reincarnation of them.
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