Yes. Just like Red Libra you can change weapon. Dragon Cutter to Dragon Bow. Dragon Retributer to Dragon Dagger. Just pay a small sum of adena.
Should be out next month i guess.
Since when 1Ncoin cost 15mil?
At least in CHRONOS, it's about only 12mil.
With event usually items cost lesser like 10mil or lesser if you set buy shop.