Have you filed your 2019 taxes yet? if so, those dependents should be picked up when they calculate the stimuls payments. If don't file before the payments are created, it will work itself out when you file next year.
I've come across more information on how these stimulus rebates will work. The link below is the best analysis I have come across and should help a number of those on this thread understand 'who claimed who' and how this appears it will settle out:
https://www.cbh.com/guide/alerts/cares-act-what-you-need-to-know/
(scroll down to "Recovery Rebates")
Basically, the stimulus payments are an advance against 2020 tax returns.
When we complete 2020 tax returns, we will each re-calculate the stimulus payments based on 2020 tax returns (income, qualifying children, etc).
Whatever that re-calculated number is LESS what you already received will be an additional credit on your tax return, which would increase your refund or reduce how much you owe. Let's say you didn't claim a child in 2019 but did in 2020 as an example that could create the credit
And here is the kicker, if that recalculated number is negative (meaning your stimulus payment was higher than you were really entitled to based on your 2020 tax return), YOU WILL NOT owe that money back. Let's say you claimed a child in 2019 who was 16 but in 2020 they were 17 as an example on how the recalculated number could be negative, (a 16 year old is a qualifying child for the $500 but the 17 year old is not eligible)
