Two questions for the price of one:

Will 19 y.o. permanently disabled special needs child living with parents receiving SSDI qualify for a stimulus payment if claimed as a dependent (ie parents provided more than half support) on parents return in 2018, assuming 2019 return was not filed?

Would child qualify for stimulus if parents didn't claim as dependent (ie did not provide half support) on their 2019 return?

The $700 question:  Trying to figure out if taxpayer gets $500 qualifying child credit on their return or child could receive $1,200 stimulus on their own.

I'm finding conflicting SSDI information out there so if anyone knows where to find definitive guidance, I'd appreciate it. (the SSA website was not helpful)