Semi-Formal or Dressy Casual. Please note that the venue is an indoor/outdoor facility located along the Potomac River, so there may be a slight breeze.
Yes, as long as they are cute and you include them when you RSVP.
What, are we monsters? Of course. We took this into account when selecting this date.
Your guess is as good as ours. It will probably still be warm, but hopefully not too humid.