Consider me highly sceptical.
How Aija once dramatically declared to her parents, “Ladies and gentlemen, welcome to the end of the world!” and curtsied.
“It’s a little disturbing to hear that from a 2-year-old, especially in the middle of a pandemic,” Marie says with a slight laugh.
Tucker nods. “You kind of wonder where she even picked up the expression.”
Because, yeah, there were absolutely no individuals on TV or radio who sarcastically remarked during the pandemic "ladies and gentlemen, welcome to the end of the world!" Just because the parents didn't remember hearing it, doesn't mean the child didn't hear it and emulate it. Childrens' brains are wired to pay attention to their surroundings in ways that adults aren't, because that's how they learn. It seems massively more likely that the children in these cases are echoing things they have heard and absorbed that their parents simply paid no attention to.
Unless the parents can categorically prove that, for example, they never watched a film or documentary about the Holocaust while their child was nearby and able to hear it, that seems a far more likely explanation than reincarnation. For that matter, I'd be more inclined to believe that the child was remembering details from a documentary the parents watched when the child was still a baby, and thus considered unable to absorb anything at all, than believe the child was remembering a past life.
The fact that they can never be pinned down to a specific historic individual is also suspect. The article gives a generic "Presumably there were a lot of Ninas in concentration camps", but okay, has anyone checked how many there were, and what ages they were, and what other details might match up with the child's story? A bit of research would prove it one way or another, and the reluctance to follow through on that research makes it hard for me to take the claims seriously.