I own a monster museum at a renaissance festival. Witches are pretty badass alone, but they are also linked to werewolves and Hags.
I tend to make my witches more hag like in appearance than vanilla witches.
Watch "Legend" with Tom cruise, there is a great Hag in there called Meg Muckle bones, another great hag is called Jenny Greenteeth google them because they are awesome. the witches/hags in "Beastmaster" are also pretty cool looking. Also look up Baba Yaga....
I would definitely go stilts for the character to make it larger than life. 7.5-8ft tall would be plenty. In the past I have done "Hag huts" as sets with shelves full of spell components, herbs drying and hanging from the ceiling, magic circles and all kinds of detailgasm strewn all over the set, tons of chances for eye candy in a witch set.
A witch haunt could be awesome, it could span from collecting spell compoments (bat cave for bat wings, a graveyard for the finger of a birth strangled babe, ect...)to summoning a demon, an alchemy chamber where they are creating a homonculous, making the salve to turn a man into a werewolf, creeping into a pregnant womans room to lay her hand on her stomach and steal the baby. So many creepy creepy things that ypou can show and do with witches, cannibalism, orgies with demons that are possessing animals, a candy house, an oven for cooking children so many things are creepy as hell if you take them seriously.
So flash concepts...
Three witches at a cauldron
stilt hag attack
summon a werewolf
stealing the corpses of hanged criminals for components
taking the dirt where the hanged mans seed spilled to make a Mandrake
standing over a fog machine vent so smoke billows up and out their robe
Swamps and water are great set concepts
There is so much you can do and so much lore to rob Im sure you will get a great show. If you want to call and talk over a few concepts then please do, Im happy to help.
Allen H 469-337-4929