Spiritual attacks probably refers to yin or yang transformations.
I would say definitely not 360. It's a shield. Maybe it can change radius proportionately to size of susanoo or maybe tweak its shape to be more or less elliptical. But definitely not more than 30-45 degrees.
I would say that it can block physical attacks, meaning dissipate kinetic energy if TSB can, BUT it can only do so for attacks on mirror. What I mean is it can stop susanoo sword but it cannot stop rinnegan's push or pull unless user hides himself behind it, which would mean leaving only rib cage and hand of susanoo. If not other parts of susanoo would be affected. It cannot block Chibaku Tensei because it is omnidirectional and mirror is frontal so susanoo would be in crazy spinning motion and the user would be in worse situation than without mirror. if for example it can dissipate kinetic energy and we imagine scenario where susanoo with yata mirror lifted above its head, tries to stop Tengai Shinsei it could stop motion of Tengai Shinsei upon contact but it couldn't do anything about its mass; either the susanoo collapses due to user's fatigue or it sinks into earth under weight of the asteroide.
For other questions there aren't any information. I would say it can negate one NT at a time. WHY? Subjective. I get the feeling that YM is solid, while TSB are fluid. So solid is kind of digital while TSB is analog. That would also be a reson why I don't think it can stop kekkei genkai. Can it block kekkei genkai?If it can block every single one NT it doesn't mean it can block combinations.
I would say that senjutsu also works. If it works against TSB than...