I can speak for plant care within a live terrarium setup, but not specifically for cresties.
you need to balance soil depth, the substrate itself, the types of plants, their needs, proper spacing between plants, etc.
I have made dozens of live plant setups in my cages over the years, nothing extravagant, but still beautiful and simple (all cages were 55gallons or smaller).
The soil I am currently running in my bearded cham terrarium is peat moss, vermiculite, and some cocofiber. The peat moss is perfect for humidity, the cocofiber helps give the soil some more substance/filler of a different kind and the vermiculite is great for the bottom layer to allow the roots to easily suck up water once the roots are set in and growing. just go dig a hole in your yard and look how the soil is stratified, you'll see their are different layers of different types of dirt, just try and mimic that
I have used ferns, hibiscus, ficus, mini palms, orchids, bromeliads, etc etc if its tropical. i've used aloe and non-spiny desert plants for dry setups (tarantulas, etc).
Just make sure to keep the soil wet, but not too wet. You don't want fungus or molds to grow. Also clean up ANY and ALL fallen dead leaves, that can also gunk things up. Adding some earthworms can help the soil stay clean.
this may be of no help to you, but it might. I figured I'd try.