I am not sure what 9000 hits on google scholar tell you about research she has undertaken and published as opposed to her reviews of other people's research and how recent/relevant it is. incidentally I keyed her name and didn't get anything at all - I must have keyed something wrong.
In any event her research finding 'nothing' doesn't really take us forward in assessing the evidence from other sources of which there is a great deal.
It would be very difficult for Stevenson to 'prove' reincarnation. If one accepts survival may be possible, there are other potential explanations for most reports of reincarnation.
I don't have a particular interest in reincarnation myself but the question perhaps is: are the experiences he relates true or not? Whether he rejected stories which didn't support his ideas seems to me less relevant. He only needed to find one case that couldn't be explained other means. I think he was looking for evidence to support his contention, not conducting a dispassionate analysis of aspirin compared to paracetamol. :)
In that sense was simply bearing witness to the stories he was told and which he tried to validate as far as he could. Was he biased? Almost definitely. Do we have to accept his interpretation of the tales he recounts? No of course not we can read them ourselves and form our own view.
What kind of witness was Stevenson? Difficult to know - I suppose he had a motive to lie if his aim was to prove reincarnation but that doesn't mean he did lie.
Does the fact that he had cock-eyed ideas about disease invalidate the stories he collected? Not necessarily.
Have you read Stevenson's research for yourself Cofty?