Slit Harem

I was thinking:
Oompa Loompa:
Purple high-waist shorts, purple/or white braces plus a coloured vest (which colour??) plus heels (what colour, plus what to wear on legs? etc)

Belly-dancer
White jingly top (will change round a belly dancing belt for this..)
white harem pants (with slits) and..white heels?
Or could I get away with another colour shoes?
Any good retailers that you know of with white harem pants?

Mermaid:
Aqua sequin leggings, frilly blue top.. blue heels?

I only have black heels so any other thoughts on what I can wear/and where to get them from, and which UK internet/shops will have some cheap clothes are welcome

Also other outfit suggestions are welcome

Lots of people are going as vampires/st trinians etc, but I want to be fun