We don't have to relied on corocoro anymore...smash could show us something...or even a direct nintendo video..and for the international players the main site cold be updated anytime! but I don't expect anymore legendaries mons being reveal until the released!!
I was just thinking about BST for Xerneas and Yveltal and I'm thinking 670
well considering the cover legends have had a BST of 680 for the past two gens (maybe longer i haven't checked) I think it's safe to say that will stay the same.
also I think Yveltal will be a defensive beast like lugia was