Just go in on Monday. Go in with a smile and apologize profusely for not knowing it was the anniversary of the the late King's death. You should be fine. The late fee should be waived if you al really apologetic you be fine. But you should always check the reporting date does not fall on a weekend/holiday.
What Visa news? Seems all will stay as is except for the new Long Stay. O/A insurance coverage might go down i hear but nothing confirmed as of yet. Maybe by the 3rd... but who knows. Entry tourist tax is set though....555