Past-life memories research and karma

I think the issue here is that young children remembering previous lives are much more attractive to study because their minds are less influenced by other things. How, for example, would you 'prove' that a patient aged 30 (say) had not read something that inspired their feeling of having lived before.

The issue of adult reincarnation recall, whether via hypnosis or spontaneous recall, comes up against that standard objection. i.e. the possibility of having acquired knowledge from some mundane source.  One way to respond to that objection is to identify verifications in obscure locations, of various kinds. One example was a woman, from Australia I think, who recalled some detail of markings on the dust-covered floor of some disused old barn or old stone building in England, a place she had never visited. Such information simply isn't available by any ordinary means.

It might be interesting to contact Tucker and ask him if he thinks hypnotic regression is accessing the same basic phenomenon.

I'm not sure of Tucker's views. I know Jim Matlock is quite dismissive of hypnotic regression. When pressed he explained that he wasn't saying that it didn't ever give valid results, only that the possibilities of the mind having created a sort of false memory or other complications meant he recommended to avoid it. I tend to think he is too harsh in his evaluation, but these things come down to individual opinion.