Hi from twst. heres the spoiler but ill answer it with a twist:
*is this their original personality?
it is a mix of 'their' personalities.
*what Crowley did to them?
just the memory altering thingy magic.
*Did they came from another world? or theyre just a child from twst world and have their memories by crowley.
Not a strong yes but Yes.
*The 'he' that they have memories of is most likely Crowley?
Wrong. Its related to the first Q.