My event ideas:
1.Like last valentines days mass event mass 2 people would partner up to make a creative costume couple , there could be one for haloween costumes . For me this is a good idea as instead of getting most people vs each other they will have to cooperate with friends to make a nice and creative entry
2.If the candy ghost idea is completely reworked I think it should be more like the Easter type of event in terms of candy collection , this way there won't be 263 players hogging one ghost and get mad over not getting it which can often lead to harnessment :/. The egg collection system in my opinion would work better now for candy collection . I don't see why a trading candy system here would be required so that could be taken off.
3. Egg gift shops :
Once a person collects a decent amount of eggs they would be able to go into a gift shop where they could purchase a series of hats or items, but there would be multiple rooms which require you to attain a certain amount of eggs before entering , so if a player who she's to exore it then they better save their eggs

. For this option I sugest if possible placing the same exact shop in 3-5 different locations so that people don't all crowd around one shop and create lag :/
3. For the older players in the community I think that there should be like a mini use for old rotten eggs :0 like maybe you can use them in a special vending machine and test your luck in getting something good

, I just think it would be a good use for rotten eggs and as not everyone saves their rotten eggs not many people would crowd over the vending machine ( hopefully )
4 like it happened before , half prove customs and maybe some cheap bodies Halloween themed in refuses house wouldn't hurt ;)
5 maybe a mini secret dungeon quest that would give you a special mount or morph , this would be hidden and not fully anounced to players so that they have fun serching with friends
6 if I which hunt or similar is presented , then have her appear in different places at once to help not to overcrowd and help the hight player count balance out a little
7. BLOB , why not replace it with a giant pumpkin that will drop special haloween goodies

all that hats to be changed is the blob an items so I don't this it would take a massive amount of work to do and many people can get involved in it at once
( keep in mind I'm not asking for all of these they are just ideas that popped out into my mind )
Item wise :
Like last haloween there could be a special 2 p mount like maybe a big punkin , a big ghost... Etc