Dunno, despite being one of the worst for taking ethical picks up to the line, I'd struggle with kids. And, oddly, it does strike me as really bad taste in dead pooling when - like cash for cadavers - there is money/betting involved. As per usual this isn't simple because rules would admit an adult case with severe learning difficulties who may actually be as infantile as any child we would avoid picking.
Allow me to throw in a different perspective. If I knew of a child that is close to death and a celeb for reasons other than being close to death, e.g. a child actor, I'd have few qualms about using it as a deadpool candidate. Of course this happens about as often as I win the state lottery.
The unfortunate Jahi would not qualify, not because she's a child, but because I don't select "famous-for-being-famous" or "famous-for-dying" candidates.
regards,
Hein