Will the co-pilot hours logged in the current system be backdated to 1 to 1 hours in Part 61?
As someone who has filled in innumerable forms for different governments & employers, each with different rules about logging flight time, here is my advice.
Complete the flight time form as if every hour in the logbook has been flown under the rule-set pertaining to that form.
Back-dating is an inappropriate word in the circumstances, but the basic answer is Yes. Under new Part 61, you cease to care about logging 50% of flight time - for any flight you've ever done.
And the definition of night is going to be between evening civil twilight and morning civil twilight. That's different to last and first light.
Based on the AIP, I thought that first/last light carry the same definition as MCT/ECT. ("For all intents and purposes" they are the same.)
Out of historical interest, does anyone know the precise definition of first light & last light?