RE: should it file a California return, apportioning all income out of California, and pay the minimum franchise tax for 2021?

NOT merely recommended, but definitely yes.

CA corporate tax for year 1 is for the privilege of doing business in year 2.  See California Revenue & Tax Code Section 23151.

Then you may ask, how about the final year?  Section 23151.2 basically says the final year's franchise tax is for the privilege of dissolving or withdrawing.

BUT, the corporate tax for the first year is waived.  Who says CA is not business friendly?