Hi Atom
atom III.sib: I'm not sure what you imported into this file, but the noteheads list has become corrupted. The S7S noteheads list should only go up to 63, but this one goes up to 64. This may not have a bad affect on things, but it could. See attached image. And you can compare this to other files also, if you want.
It also appears that this file contains the "S7S Library 7.1.2" instrument definitions. Again, it shouldn't be a problem, just telling you what I see.
atom II.sib: This file looks OK to me.
Atom, I guess I'm back to where I don't understand what trouble you're having. After you merge House Styles, what is the error/issue you see?