You are correct, neither will qualify for the 2020 $500 child stimulus.
Q. 1. My 17-year-old son earned a few hundred dollars last year. Would it make sense for me to amend my tax filing to not claim him as a dependent, have him file his own tax return, and him get the full adult $1200?
A. 1. No. That is not allowed. If he qualifies as your dependent, he can not file independent. It's not optional.
Q. 2. Is there any provision made for the newborn (I heard if she is on next years' tax filing I would receive the payment with that return?)
A. 2. 2020 rules are not clear yet.
