Don't be sorry, and have fun with SunFlow, alone or combined with Sweet Home 3D. [:)]
I just wanted to insist on the fact that it's not reasonable to spend more time on a library that is not maintained, moreover if there are a few bugs in it. By the way, SunFlow doesn't use Java3D at all, and the biggest part of PhotoRenderer class consist of adapting Java3D data to SunFlow data.

I know the illum 0 MTL parameter works, since it's taken it into account in SunFlow parametrization. It's just you might be the first user to try it! [;)]
As you (almost) noticed in the code, the fact that a material uses illum 0 model is stored in lightingEnable property, set in OBJLoader class and read in PhotoRenderer class. But OBJLoader class doesn't read Ke values because I don't see it in MTL specifications (but maybe they are not up to date).