Unfortunate in more than one sense because adopting a fiscal year doesn't work (it would end on 12/31/16 anyway) and you are past the 65-day (Section 663(b)) period for making distributions after the close of the tax year.
However, keep in mind that if the will (or trust instrument) requires that income be distributed currently, then the income that accrued in 2016 is treated as having been distributed to the beneficiaries even if it was not actually distributed.
