I think that this theory is unbased, because when link comes back to te present after killing demise, the statue still is there because link didnt stay in the past to change future, or present, when he comes back the statue still should be there because its "descending" already had happened in...
I liked it, it was a little challenging, because you needed to have a perfet timing shield bash to not take damage, buti thnk ghirahim's fight was more challenging
I dont think she is annoying at all, i mean, yes she beeps every time you hearts are low, but just dont press the button and she doesnt pop up! Really simple.
I dont think ss is in two separated places, because even link placing the master sword in the past, in the present still there's no hyrule, and i think link and zelda form the royal family in the end.