@raggedyak , for the federal return for tax year 2023;
(a) first year choice is really for tax payers whom while not meeting the SPT during the tax year but expects to meet this test during the following ( in addition to a few other caveats .
(b) for your particular case --
1. you are married to a US citizen/ by the end of the year.
2. you are dual status for the year 2023 but at permanent resident by the end of the year.
3. Under section 6013-6 you can indeed request to be treated as a resident alien for the whole calendar year. This also means , as you have articulated in your post -- you can use the standard deduction along with your spouse. ( article 551 at www.irs.gov )
4. your world income is included for purposes of US federal taxes.
5. since you were not a US resident till Jan 1st of 2023 ( by virtue of exercising section 6013-6 ), your tax home would not meet the 340 out of 365 days and thus you cannot exclude foreign earned income. However , because US is taxing you on your earned income from UK during the tax year 2023, you have the option of either deducting the taxes ( if you itemize under SALT limit ) or claiming foreign tax credit.
For the California return:
while you can file as married filing sep -- on form 540-NR or file 540 but exclude you UK income as earned outside the state, ( your residency in CA started on say 7/25/2023 and you earned income outside the state 01/01/2023 till 07/01/2023 , etc. ) and have been taxed by another country. I would suggest for you to call the California Franchise Tax board and ask for help on this. They generally are quite helpful.
Is there more I can do for you ?
pk
