I’m currently working on a whole book about the very subject! It’ll be the price of totally free but I’m waiting to finish my point and click book before continuing. We’ll be covering the turn-based AI, Limit Break system ala FF7, World map system (Two of them! One like FF7, the other like Legend of Dragoon), Transformation system similar to Legend of Dragoon and how to create pre-rendered backgrounds (As an optional extra) as well as a whole load of neat tips and tricks to make sure you can craft your own dream RPG games!
To be honest the best way to do combat would to have the combat scenes a child of the persistent level and simply switch between the two having a UMG fake load screen to mask the transition. It looks better, is faster and a nice easy way to get a nice looking game FAST. 
But yeah, It’ll hopefully be out in a month or two, but you can check progress on the KITATUS forums (Click me!))