Hallow's mind is complex. Her thoughts are organized in such a way that nobody understands but her. She speaks in hints, not exactly telling all, but leaving you to try and figure out her meaning. Surely a Halloween Cat wears masks, but is it one you expect? Bunnymund didn't expect it, but now that he knows, he feels empty. After all, there's nothing he can do.
Growing up in Berk, Hiccup may or may not be falling for one of the older boys, Jack. Jack, for his part, still saw him as a child. But what was the hurry? They had a lifetime ahead of them.