Most plants you can completely rinse off and then just plant straight into the coco fiber substrate, but build your tank with a stone, clay ball, or eggcrate false bottom with a screen between the false bottom and the coco fiber, so you have good drainage.
Bromeliads do better if placed into a piece of cork, wood, or into the background since they don't need soil to live. If placed directly into a substrate that is always wet the base of the brom will slowly rot. If your substrate is only damp near the top and you have good drainage, then the bromeliad will do fine in the soil.

To attach things to a branch or vine, some people will hot glue it to the accent or sew in place. I drape it over or just wrap it and hope it takes and roots to the branch or vine.

One more note on bromeliads, they will grow when just pushed into a hole in a background and will root to the background.