In a way ..I did and no they are not in my life ...they didn't stay in it for long which is fine...people change

Do you mean in a literal sense? I think that for me, reintroducing myself would feel unnecessary because they will quickly notice that I've changed. Maybe I would just tell them a bit about the things I do differently now, or views that I've changed like: "Do you remember when I said I'd never want to quit smoking? That was so silly." Idk, something like that lol.

No, because eliminating certain people from my life was one of the things that allowed me to change from someone I didn't like very much, into the me that I was always meant to be.

No, I never assume someone who didn't like me before would like me any better now.

haven't done that yet, seems fun to do though!