craftgrrl | New member, need some help with costume

New member here, I looked up this community just so I could ask some questions to you more experienced types out there. I have this (incredibly nerdy) costume I want to make, and I need a little help. First, the picture. (hope this is appropriate)

It's Paine in her Black Mage outfit from Final Fantasy X2 (see? I told you, nerdy!). Each of the 3 characters have their own outfits, but hers is the one I like best and the one that seems the most doable. I'm on this thing this year about being a witch for halloween, but I didn't want to do the typical witchy costume. I really like this outfit, regardless of where it's from, as a witch costume.
The pants, sleeves and little black top should be fairly easy to put together, but I have NO idea how to make a hat, let alone one that large (I would like to make it a little floppier and maybe not quite so big) and the red corset-type thing I'm a little confused about how to do. The black oversleeves could be done in simple black fabric with gold paint, if I didn't have a lot of time, but I could also sew on some kind of cording or trim or something to make those scalloped shapes, couldn't I? Of course if I was very ambitious, I could make each scallop, trim it, ad then sew them all together, but I don't know if that's possible. I'm only a level 1 seamstress, but I have some friends and family who could help me. I don't have a sewing machine at home yet, but I will be getting one soon (an antique foot-pedal one), just not sure if it'll be in time for Halloween (it should work but might need some fixing). The wand/cane thing shouldn't be too hard either with paper mache (and other supplies from the trusty dollar store).

I found a picture of some girls who did rather a nice job on the three characters...

It looks like they made the hats out of foam and covered them in fabric. The one I want to make is in the middle. Click herefor a picture from the game of the one on the left (Rikku's outfit) and here for the one on the right (Yuna's outfit).

Sorry about the ramble. If anyone has any suggestions, please let me know. I'm sure I can figure out most of the sewing, but the hat and cane I'm going to need some help with. I have a bit of dowling I think I can use for the cane, but what should I use on the top? I don't have to make the the exact same topper, but I want something that'll last being hauled around. Thanks :)