is it possible to let a project e.g. 'MyHouse3D' refer to its own .xml instead of having all projects referring to preferences.xml?

It's already the case from the very first version of Sweet Home 3D able to save homes. Thus, you can send your project to anyone wherever his furniture and textures catalog is the same or not.

Maybe you found a bug bound to antialiasing but that would be quite astonishing. Please, share or send [url=mailto:[email protected]]me[/url] a project that lost its textures, and I'll check how it works on my side.