I believe that they are fine to use since the RPGMaker title labeled "Theia - The Crimson Eclipse" uses them and I haven't heard of them getting into any legal trouble. Hell, it's been out for years and no legal issue has arrived at them yet I believe. It even uses a song from Chris Redfield's first campaign mission from RE6 (as I recognized it immediately when it played, having gone through RE6 a few times over on my 360/PS3 and all. This is the theme in case you were wondering:
though it cuts off at around 1:28 for the Theia variation of the song used) no less and Theia still has it in its current version so needless to say they aren't in any legal trouble, though I can understand your hesitation. Although they DO show a note at the startup of Theia to let any and all know that all original material used in Theia belongs to their respective original creators and in no way belong to them as detailed in this screenshot: 
Unfortunately, I don't know the original authors of the two songs I showed you (I was originally going to include this one here as another suggestion: https://soundcloud.com/user-954439293/dungeon-9 but then I thought it didn't infer enough of a "dread type of feeling" like the other two do and instead it feels like a more "courageous" feeling instead, so yeah... ^^; ), though as long as you detail that those songs weren't created by you and give out a note similar to the one shown in the screenshot then it should be alright.