Like aguzo said

Gosth candy hunt was fun but it was a lot of work for the gfx team as i heard (i wasnt there)

Im not for a guild event since its up to player to play solo or teamwork

A custom event would be great, but it wouldnt be a weekly event like the usual one on graal so there should be another event in the same time (candy hunt or gosth hunt or something new)
Something i think would be disturbing for the custom event would be :
Only gfx player could win (even if there is alot of great gfx in this community, some are from the graphics team sooo)
It would be better if player could pick winners but the only way i see is the same one from the old system where player could give some idkanymorethename points but like before, some people would just afk at balamb and as for the new players to give them out some pts
(well maybe we could only allow the +100hrs ppl to do it)
If i think in another way, we could make this Halloween fashion show like the one coco made from St Valentin but it was her who chosed winners
We could have some judge
Ughhh I'm thinking too much
There is probabily others way to host this Halloween fashion show if it will be hosted i just wanted to more specific