there is no such thing as "splitting" when it comes to the IRS. Only one person can claim the child.
it's uncertain how this will work out given you filed in 2018 but the father filed in 2019. I have to believe the IRS will do some sort of social security match so that the same child isn't eligible for $500 on two different returns.
What makes it even more complicated - and this isn't widely reported yet - is that these rebates are really an ESTIMATE against your 2020 tax return to be filled out next year. So whatever is on your 2020 tax return (income, dependents, etc) is what the ACTUAL rebate is based on.
if that ACTUAL is more than the ESTIMATE, you will get additional credits on your tax return.
if that ACTUAL is less than the ESTIMATE, you don't have to return the money.
best advise is just sit back and see how it all works out - a lot remains fluid and unknown,
