The govt rules are clear for CA residents in disaster counties, but do I need to use the "Payment with federal extension" and "Payment with state extension" options in TT Desktop as a CA resident who took advantage of the extensions?
It depends. Taxpayers who fall under the CA tax relief declaration and are filing and/or paying on or before June 17, 2024 do not need to request an extension. If you need a filing extension beyond June 17, 2024, you should file a request for extension by Apr 15, if electronically filing. If taxes are expected to be due, you should make a payment with that extension to avoid penalty. You may do that using the "Payment with extension" option.
"The IRS urges anyone who needs an additional tax-filing extension, beyond June 17, 2024, for their 2023 federal income tax return to request it electronically by April 15, 2024. Though a disaster-area taxpayer qualifies to request an extension between April 15, 2024 and June 17, 2024, a request filed during this period can only be submitted on paper. Whether requested electronically or on paper, the taxpayer will then have until Oct. 15, 2024 to file, though payments are still due on June 17, 2024."