Tillandsia's are really neat! Tillandsia is in the bromeliad family and not a succulent. Many come from tropical rain forest regions with high humidity and indirect light. Tillandsia ionatha  is able to be in direct sun. They do not require soil and having them in moss will rot the base. I wonder if the reference to succulents was because of their tolerance to dry situations. I have included a link for you to view to help you determine how you wish to include them in your wreath. http://www.bromeliads.info/best-bromeliads-full-sun/