Actually, I'm using Blender for creating these entities, but there are problems with the output, i.e. Blender exports an environment light (even if lights are disabled in export), which creates issues when compiling the package).
Also, I need to assign new materials in Composer Pro, as I need universal inputs to alter textures at runtime in my scenario.
I understand references, but the funny thing is that somehow (still haven't figured out a sequence of steps how to do it) I manage to convert these references to original data within the scene. These data are kept even when removing the originally referenced *.usdz.
For me that makes stuff so much easier than dealing with the exports from Blender.