Gimp for photo/image editing and artwork, RPG Maker MV
So it must be the plugins then. As I looked at the different variants of RPG maker I couldn't find a layout like you have. I admit it was kind of annoying when I first started with it but it has grown on me that is why I was curious. Was wanting to see how hard it would be to emulate it. I have an idea for my own game but keep getting stuck with not liking how it would work on the various tools I have seen so far.
Probably better game engines to use besides rpgmaker for a game like this, but I’m very visual so this works for me. Most of the game relies on the clickable events plugin by yanfly as well as his quest engine. The interface elements are made using a few parallax background images and clickable events made to look like buttons.