Agree with much of what has been said here. I can give you my perspective. I'm in a unique situation because, like Jenny Cockell, I have been in contact with my former selves family (namely the son). Through him I have been able to verify very personal memories that only his dad (my former self) would know. The reason I have not posted too much info on here about this is not because I do not want to share this story, but because I respect and value the privacy of the family.
I decided to contact Jenny Cockell when memories of my former self started to surface. I had the opportunity to contact the family of my former self because of the unique circumstances of my former selves death, after much thought, and coincidences, and advice from Jenny, I actually went ahead and did it. Before contacting the family (the son) I was able to verify one very vivid memory which was my previous selves wedding day. It took a couple of months of searching but I managed to research that memory through online newspaper archives and internet resources. That gave me the courage to go ahead and contact the family since I could see for myself the visions I was having of my previous life were not mere fabrications. The son confirmed for me what I had seen of my wedding day memory were facts, such as the fact his dad's brother was serving in the Navy (he was the best man, the son didn't know this but I confirmed that through a newspaper article), and the biggy, which was that his mother was pregnant with himself at the time of the marriage. He confirmed that the wedding day was very tense, as I saw and felt directly, and I showed him the photo I found of the announcement of the wedding which showed his mother how I had seen her in a gown with long sleeves, a cinched waist, a full skirt, and white flowers.
After that we have corresponded a few times via the internet, mostly because his dad's fate is unresolved (he went MIA during Vietnam War), and my memories, if true, point to some interesting avenues. We have discussed some events of his childhood, such as a memory I had of him cutting his hand after he was playing with a knife that had belonged to his dad. I couldn't figure out where the parents were at the time, as he seemed to be alone with his sister. The image of him holding his hand and there being a lot of blood, and he and his sister both crying kept repeating to me. He confirmed to me that he had indeed cut his finger on a knife that had been his dads when he was young. He had been alone with his sister at the time and his mom had been out picking his dad up from the nearby base. He said his parents came back to find him a bloody mess.
This just an example of one memory that I was able to confirm via him. There's about six or seven other memories that he's been able to confirm because they relate directly to him.
Other memories link to my own childhood. As a kid I used to go off and daydream, and in these daydreams I used to sing songs that would come to me fully formed. They were strange songs about love, and loss and heartbreak, usually. My parents and sister confirmed that I used to do this . Now when recalling these memories I started to recall songs like this when I was dropping off to sleep. One of them stuck in my mind and I typed the chorus in Google when I awoke. Turns out it was a real song from 1963, a Country and Western song that was really vague and didn't even make the charts. It was a song that would have been a number on an album, probably not released as a single. It had about 4k views on Youtube. I didn't even know the artist, never heard of him, and not been exposed to that music growing up.
Looking at my memories there's many more facts I've been able to link, or verify to real events. I've not counted them all yet, I'm in the process of doing that. Despite all this, I still have a very strong doubting mind. I can see its true, and its linking to real things, but I'm always under the impression that all my memories are suspect till proven otherwise. I'm a person who needs facts. Then there's the undeniable truth, which has exposed many things to myself. It's not for the faint hearted, and I think my subconscious didn't reveal any of my former life memories to me until now for that reason. The other reason it has come to me is because I had left a big chunk of unfinished business that needs resolving. But remembering has settled a feeling within me that I've held since childhood that I was missing something important. It was such a restless feeling that would come and go in waves, and now, finally, I know its source. That's bought me some peace in itself.