Well, they say that transferring resources between Ace and MV is easy, but they never said it would be easy the first time when you "don't know what you're doing".
Numina, another RPG Maker JRPG in the making, was even transferred from XP to MV, and as a result, the developer and the testers struggle(d) with bugs on every map. Hopefully, you'll be spared from similar issues.