Both can be put into the enclosure, just make sure the bromelaids you choose do not have an sharp/jagged edges. You're right, just wash the soil off and plant in the substrate. However, straight cocofiber is not the best because it can become waterlogged causing the roots of the plant to rot (unless you have a drainage layer). According to New England Herpetoculture this is what type of mixture is best for plants: "Our substrate mix includes blended fine & medium grade tree fern fiber, fine & medium grade orchid bark, chopped AAA grade New Zealand sphagnum moss, coir, and fine & medium grade organic charcoal. Coir seems to resist breaking down & compacting better than peat moss, and it also gives a rich darker texture to the soil as compared to other mixes." I'm sure there are other suggestions out there, too. Also, I would let the plant grow in fresh substrate for a month before you put it with your whites. That way any fertilizer or what-not that was used on the plant has a chance to grow out.