I can't tell will It work with RPGG Maker MV because I didn't use It.
It should work with any game engine that supports hex tiles.
Yes, you can use It in a commercial project. I don't think there's a specific license in this pack right now, there was no need so far.
You can contact me via e-mail to clarify any details ( kac.wozniak[at]gmail.com ).
My name is Kacper and I'm a pixel artist / IT student. I knew about Superpowers from Twitter but didn't try It out until couple of weeks ago. The fact that is a HTML5 game engine with such a nice editor, open source code and amazing potential convinced me to give It a shot and I'm very happy with that.