I don't understand the question.  The 2024 estate income was less than the $600 exemption, so no return is required.  Are you saying that there is then some 2025 income?  If it's more than $600, then yes, file a 1041.  But "a mismatch of start date and date of death would be noticed by the IRS" is nonsense.  The short little man with a green eyeshade was laid off months ago.  Fact is, no one at IRS ever gave a rodent's posterior about your ten-day gap.

Or, there is still the alternative of filing the estate return on a fiscal-year basis.  Date of death through 11/30/25.  And add in that December 2024 income.