Just come in the attire you feel best for the day. There is not necessarily a dress code, and we do not judge. :)
Yes, but in order to keep a good headcount for food, we advise if you could please give us a notice beforehand.
If you can't get the registry to work, or you find that it is too complicated to use, don't worry about it! If you have it in your heart to gift us something, you are more than welcome to bring it in any form on the wedding day. Please note: You are not required to have a gift to attend! :)