Okay, to make things clear you can get everything from the mcl halloween event and without using your ap. Actually if you manage to achieve all the five keys every day for the length of the event you’ll have all the clothes plus the illustrations.
The event will last 12 days -today included- (5keys x 12days = 60keys in total) and this means that you can get both illustrations (6 pieces each) and all the new stuff (44 items) total of 56.
You just have to be patient.
I hope what I wrote above makes sense and that helps :)