I understand the points you're making about not being able to put the same child on two returns. But let's assume Parent A is legally entitled to claim their own child A because their contract with their ex-spouse allows it and they do pay for all of that child's expenses while living in the house. And Parent B can legally claim their child B because their particular contract allows it and they pay all of Child B's expenses. So at minimum Parent A should be able to put their own child's SSN on their return and Parent B can legit put their child's SSN on their return. So if the common expenses for the house and for child AB really are 50-50, then I assume the parent with the higher income would claim the child AB on the return. Let's say that's Parent A. But the HOH question is still unsettled. If the expenses for AB and the common house expenses are really 50-50, then can the parties just make an agreement between them on which will use HOH on their return? Let's say that's Parent B. So then Parent A will have their child A on their return and the common child AB but will have to file as single? Can you file as single but also list dependents without being an HOH?
