have you tried pleather? or pvc leather? and I know that foam core board, however weak, is very good for making weapons, or wood. sometimes both (using foam core board for details that can be easily cut out and manipulated) there's someone called babylondonstar on DA
http://www.babylondonstar.deviantart.com/ follow the link to her website and there is a reasonably good tutorial on how to make the moogle doll (if someone from your group is going as that witch woman) if you have any questions I'm an experienced cosplayer
with the X on Paine I believe I once saw it on ebay or a specialist game site I found when I was looking for roxas' necklace and I know you can get her pendant on there.
With the shoes you can always buy ANY cowboy looking boots or similar and use shoe paint (available from any shoe repair shop) to change its colour. I once changed some black shoes to brown using this stuff and they turned out absolutely fantastic, like I'd just bought them that way in the shop, and it only took an about two and a half hours (drying time within that, it dries within a reasonable time) and you usually only need the one bottle for a pair of shoes. I should know, it started raining on me so when I was running under cover in shock the bottle broke when I dropped it and I only got to use a little less than half its contents
