The Tor foundation could offer some answers or guidance. Depending on what the friction points are, it might be worth funding something more streamlined. Like an equivalent of BDK, LDK, and NDK fordevelopers to integrate Tor.

Or, even just documentation on their end. Perhaps you gather a list of questions you have and ask other developers such as ( @jb55 @Mike Dilger ) if they have any Tor questions. Pass the questions to the people working on Tor and use their answers/guidance as a starting point for development docs. 

 When i worked on the green wallet they compiled tor as a static lib and used it directly in gdk. Definitely possible if you don’t mind native integrations.