Lets see here...
Xemnas hard to say.
Xigbar in a place where his element won't do jack (but then again there is little places in the KH worlds that I can think of).
Xaldin in Agrabah because wind and sand not a good mix.
Vexen also Agrabah ice and heat don't mix.
http://en.wikipedia.org/wiki/Organization_XIII#LexaeusLexaeus hard to say.
Zexion hard to say because there are many ways one can destroy a book.
Saix being locked in a small room with no windows is good. However there are flaws to it no matter what.
Axel several places actually, Atlantica, Christmas Town or Land Of The Dragons.
Demyx Agrabah because water will just evaporate.
Luxord hard to say because cards can be cut shredded or burnt.
Marluxia several places actually, Agrabah, Atlantica, Land Of The Dragons, or Christmas Town.
Larxene hard to say.
Roxas hard to say.
Some of them are hard to say because of their elements in general. There are several places that may work but then there are some places that just won't and to be honest I can't think of them right now so this is as best as I can come up with without over lapping.