Yes it is encouraged for the reception! It is Halloween have fun with it! Just keep in mind this is Disney so be appropriate and no masks for those over 14. No Dad, the face mask you wear when you're sick is not the type of mask I am talking about. :p
If you stay at one of the hotels listed you will be picked up by a bus at a specified time. If not please plan accordingly to drive and or uber to the Grand Floridian