So I am not the only one for which this situation is new. I told this now-client that her situation taught me something I had never, in over 30 years of practice, seen.
Filing status of single is correct if "(a) taxpayer is single if unmarried or separated from a spouse, either by divorce or a separate maintenance decree, on December 31." My bold and my, because she called it alimony, misspeak. The payments are separate maintenance.
From Topic 452:
Alimony or Separate Maintenance – In General
Amounts paid to a spouse or a former spouse under a divorce or separation instrument (including a divorce decree, a separate maintenance decree, or a written separation agreement) may be alimony or separate maintenance payments for federal tax purposes.
A payment is alimony or separate maintenance if all the following requirements are met:
The spouses don't file a joint return with each other;
The payment is in cash (including checks or money orders);
The payment is to or for a spouse or a former spouse made under a divorce or separation instrument;
The spouses aren't members of the same household when the payment is made (This requirement applies only if the spouses are legally separated under a decree of divorce or of separate maintenance.);
There's no liability to make the payment (in cash or property) after the death of the recipient spouse;
The payment isn't treated as child support or a property settlement; and
The divorce or separation agreement does not designate the payment as not includable in gross income of the payee spouse and not allowable as a deduction to the payer spouse.
And I also have learned more about CA taxation and community property! This is such a great group, right? And I have a new client