The last card will have the highest priority, negating the other 2.
So you will only have pasana property, and it won't matter if you put it in shield or wherever.
Interestingly enough, the +DEF bonus from cards like pasana/sandman seem to add up, just not the element script.
Also, if you put ie; a ghostring in clip, a pasana in shoes, and a dokaebi in top hat, dokaebi will have the highest priority. If you would remove the dokaebi then shoes are the next priority. it's probably a logical order from top to bottom.