i get asked this every now and then, "can i use your music in <whatever project>"
i suppose it shouldn't hurt to just make a post about it -- you can use any and all of my songs, for whatever project you're working on. you do not need explicit permission from me to do it. the only thing i ask of you is to leave some credit, leave a link or the name of the song in the description and/or credits wherever possible. this is optional, but it'd be neat if you could send me what you're working on too, it's always pleasant to see my songs feature somewhere :]
that's it! check out my latest album Oculi
Yatsufusa
Looking at two of your songs, I'd say you already have the licensing set up correctly to reflect this. It seems likely that the artists in question just wanted to be polite. :)