IIRC, the only real specific things that we know about the Hobus supernova are that it destroyed Romulus and that it threatened the galaxy. The latter can be interpreted in multiple ways. I look forward to seeing what our esteemed writers and editors come up with.
Yeah, I think what we saw in the movie was vague enough that the authors could easily make it more complex than a simple natural supernova.
As to what The Fall refers to, given some of the teases we've been getting lately I wouldn't be surprised if it was more metaphorical, with no actual "falling" taking place during the series.