I can weigh in on a couple of these. Hip fire felt pretty weak for a Bungie game. I found myself getting frustrated and switching to ads even at close range. Strafing was decent in both hip fire and ads, but not great. Melee abilities are used whenever you melee and the cool down bar is full. The exception is the hunter's throwing knife, which seems to detect when you are in melee range and only goes off when appropriate. It was definitely fun.