How long does the Halloween event store last? Are all the items going to be gone at 7 also?

Once an event is done, the event store shuts down as well.

But all the event commons will be moved to the regular shops. Though since the price for the items are half off during the event, the prices will raise to their normal amount.

Also, I believe that items have to be manually moved into the shops, so I don't think it should be expected that this will happen all at once.

Anyone who knows better is free to correct me. ;D

Nope - you've got it right, Howdy. :) Each item has to manually be moved from one shop to another, so it may take a few days for all the event store items to be moved to their new home. :)

When Howdy says "normal amount", he means doubled the Event Store price, just to specify.