Their green cards are pending (USCIS estimates they will be waiting another 2 years for their green cards). They don't have SSNs. ATINs I believe are not for international children. ITIN seem to be only for adults?? I also read that the IRS offers a tax credit for children adopted internationally, but I'm not sure where I add that information if not in the "dependents" section.
ATINs can be issued in international adoptions, but the child has to have a permanent resident green card or certificate of citizenship. In your case, since your children currently don't have either, you can apply for an ITIN. ITINs are available to both children and adults. You'll need to submit a Form W-7 to request the ITIN.
The adoption credit is available for both domestic and international adoptions. For international adoptions, the credit can be claimed only in the year that the adoption is final.
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