@NCperson
Right. The rules are the same, but they way they apply to these two taxpayers (and the result) will be different for tax year 2024, because they will have been separated for the whole year (and possibly divorced). Mainly centered on how physical custody affects dependent claims and how a court order about claiming dependents should be handled on the return.
(If you want to really be specific, for the 2023 tax return, they follow the tiebreaker rules for "Qualifying Child of More Than One Person" on page 15, and for 2024 and future they will follow "Children of divorced or separated parents (or parents who live apart)" starting on page 13.)
