Elpizo will have to answer that I'm afraid. I never played the original Famicom version but the DS version never reset your MP, and that game is kinder to you from what I've heard. Ninja and Sage are at the bottom floor of Eureka, which the entrance to is located on the first floor of the Crystal Tower. You will also find shops for the last sets of spells and summons you might have missed, as well as the games Ultimate Weapons barring the Onion Gear in Eureka as well.