Hi Grace,
I am not sure, if a company can live 3 months without postings, so I could also think of the approach: Close the year by End of December and migrate the data as per that data to the new company which has the new set of book with changed Fiscal Year Variant (just as a reminder: create it best as "other fiscal year" Variant.)
You do not need need to run all reports, especially the Balance Carry Forward is not needed.
you then have 2016 as "shortened Fiscal" year, which you close by new end date.
Maybe you should check in advance with the auditor.
Best regards
Marlene