For ANY Jedi or Sith costume the best pattern is Simplicity Pattern #5840
http://www.simplicity.com/p-2272-misses-men-teen-costumes.aspxTo do the off the shoulder you would just need make the tunic a little longer, and put some Velcro to hold the tunic in place. OR sew it up the front and make it a pull over.
And since you can't use the dickey, you will need to make another tunic and modify it. OR you can just make the edging for the tunic in the other color and sew it on to the main tunic. Make sure you use interfacing for it and make it a little bit wider so you can mach the seams up.
For the pants, you can Goodwill them, or get leggings. If you use leggings make SURE they are not see through.
The obi pattern is included in the Simplicity Pattern #5840 (Don't waste fabric by cutting out those ties, just get some ribbon of the same color or something of like and use that; its easier)
The front obi panel, that hangs down, you can just use the obi pattern, lengthen it and sq it off.
The wig is going to be a bitch, good luck with getting it into that hair style (lots of hair spray and bobby pins) Make sure you have it on a wig stand OR on the persons head who is going to be wearing it (preferred method)
BUT
cosplayfu.com is my first choice for wigs they are high quality, and have full lace caps.
http://www.cosplayfu.com/product/Green+Wig+%28Long%2CStraight%2C+Tsuruya+CF06%29That wig that is linked is very long. So you can style it the way you need to. MAKE SURE you get a wig cap and pin the wig down if needed. This takes time and some practice so you will want to wear it a few times before Con.
Boots are going to be a pain. Try ebay.'
Good Luck, REMEMBER TAKE YOUR TIME.