Anchorage Animal Care and Control often sees a spike in loose animals on Halloween, so keep a close eye on your dogs tonight.
All the doorbell ringing, door openings and scary costumes have a tendency to excite dogs in the first place, so come up with a strategy for dealing with the ruckus ahead of time. I often put mine in a room in advance or just talk to them as kids come to the door. It usually starts out with a lot of excitement but calms down after the first few. Just make sure they don't escape.
As for costumes, pay attention to your dog. If what you dress them in is cumbersome and creates stress, don't keep them in them longer than it takes to snap a quick picture.