LICENSE: You may use these assets in personal or commercial projects. You may modify these assets to suit your needs. You can NOT re-distribute the file, no matter how much you modify it you can use it but not share or re-sell it.
As for RPG Maker, I'm not familiar with RPG Maker that much. I guess that if you can import tilesets, you should be good.
While I have not yet seen the tilesets yet, I'm sure they can be edited and added to the rpg project easily. Or at least effortlessly since it should be mostly copy/paste on any decent image editing program to fit what the intended RPGMaker version needs to read.
