I really like this topic and think the idea of ones past self is a very interesting concept to think about. Personally I’ve thought about it in a different way, specifically about whether I own my past and it’s also a question about how we own our body.
For example, let’s say ten years ago someone took a picture of me and I demanded that this picture must not be shared or posted online. Now if ten years later I ask the photographer to send me the picture and I post it online, then the photographer and I broke the rules. I certainly did not get consent from my past self. So now the question of whether or not I am my past self comes up. Most people would probably say yes, but it’s still an interesting question.
To continue this chain of thought even further one can be creative and add themes like time travel and meeting ones past self. That expands the idea to a crazy big scope of possible questions though and is perhaps a bit too unrealistic for most people to bother thinking about.
Coming back to a more realistic idea, would posting a picture of my baby self online and insulting the person in the picture be considered morally wrong? It would certainly be considered rude by people who don’t know the context. But how many rights do I actually have here? How about using it as a profile picture on social media? There’s many different possible interesting questions here.
I understand that this is opening a whole other can of worms and a different idea than the original post, but I feel it’s a similar direction and also brings up the question about the relationship between a person and their past self.
edit: Also I just now noticed that I tend to write “past self” as singular while you write it as “past selves” in plural. I guess that’s because you talk about the topic as a more continuous thing that happens constantly. That reminds me of a theory according to which the universe splits up into many different paths every time a random quantum thingy happens. I think it’s this thing: Many-worlds interpretation (wikipedia).