Yes.
Flags at half staff nationwide are for the death of presidents or former presidents or national tragedies from military style attacks. I will include terrorism but only if it happens in more then one state or to members of the US military. So 9/11 (terror attack in more then one state) or Fort Hood (Attack on US military) gets nationwide half staff but not San Bernidino.
Statewide is determined by the governor but still should be limited to those things, death of a governor or former governor or military style attack. So it is fine for the governor of Florida to have their flags flown at half staff for Orlando, but not nationwide.
Wrong. A terror attack is an attack on us all. Jeez.