if you both agree to file a joint 2025 federal return, that's permissible because you were married on 12/31/2025 even though separated. Texas has no personal income taxes so there's nothing to file for income deemed earned in Texas. As to Virginia, she might need to file form 760PY
here's a loink to the instructions
https://www.tax.virginia.gov/sites/default/files/vatax-pdf/2024-760py-instructions.pdf
