I Need Help!!!

okay, well, I'm to make a dress. Why? The reason being is because I'm going to be Mrs. Lovett for Halloween, from Sweeney Todd. I've tried to look for dresses online, but nothing seems to work. This is where you come in. Basically: I need some sewing advice.

I need to know:
how to sew a crinoline (or a good petticoat store!)
how to sew corsets, sleeves and such.
good materials.
do's and don't.

I have some pieces already picked out, and I'm going to order them later (such as fake knives, rolling pins, and the lace gloves.) My friend Suzanne is going to help me pin up my hair on Halloween, so it's really only the dress I need help with. Here's are some photos for reference:





Thank to the moon and back from anyone that helps! I really appreciate it!

Love Always, Sakura