Are these tiles all completely original? I trust you, but kind of have to ask... legal reasons.
Yup, all of my tiles are my own original handy work.
That's not to say I'm not influenced by other artists mind you; I often look at dozens of images for inspiration. My favorite works are those by David Gervais and Kevin Kinell, but I studied the mountain tiles in a game called
Queville specifically to get the perspective right for my own new mountain tiles.
Furthermore, how do you feel about me editing the sprites and then using them?
Well, I'm not too keen on direct edits of my new stuff (as in, any of the tiles without black border lines), but I'd be more than happy if you used them as templates to create your own tiles. Indeed, I'd be downright proud.
As for any of my old stuff (the tile sheet in this thread for example), you're free to do whatever you like with them. Go nuts, and show me what you come up with.