Anyways I think Inhumans should have hints of their powers even before Terrigenesis, but just innocuous enough that it's nothing noticeable as inherently strange.
Lincoln's hair constantly looked like he rubbed a balloon on it, and he static shocked people every time he touched them. Immediately after his first kiss the girl asked him if he had ever licked a nine volt battery.
Skye had nonstop tinnitus, and could always tell you where everyone is in a room, though she always chalked it up to her childhood. She complained about turbulence on the Bus and quinjets so often that everyone assumed it was just a weird bit she was doing.
Andrew had two categories in his head that he subconsciously sorted everyone he ever met into. He never quite realized that he did it, but it was always there in the back of his mind. Skye was the first and only person to go into the third category.
Yo-Yo was always the fastest kid in her grade. At everything. She won every race, finished every assignment first, was always at the front of the line. She got to high school and was immediately scouted for the track team.
Raina always had inescapable deja vu, and frequently recognized people she had never met before. She had really weird dreams for as long as she could remember, but she never quite remembered them when she woke up.
So on and so forth.
