As for licensing problems with the Hobus storyline...
... even if Pocket can't do that story itself, surely it would be possible to do stories depicting the immediate ramifications of the fall of Romulus?
That is essentially how Mark Winegartner's Godfather novels work. They weave around The Godfather Part II and The Godfather Part III without actually touching them. The Godfather Part II happens in the middle of The Godfather Returns, and the second half of that book and The Godfather's Revenge build up toward The Godfather Part III, all without actually referencing the movies because they were licensed by the Puzo estate and not Paramount and thus could not touch Paramount's material.