This is sort of a generic answer, as I don't know how big an Exo-terra is, or what size you mean by "small" fishtank light.

That plant is a good choice for almost any terrarium big enough to hold it. The "heat lamp" I worry about, as those aren't the best thing for any plants, but if you locate your plants/cuttings more directly under the fluorescent light I expect they'll take off, and you'll be trinmming it back within the year.

In humidity that high you don't want to bury the roots very much. It will make aerial roots that cling to wood and rocks, and probably even to glass and plastic, as it tries to climb out of the tank :) Just keep redirecting it and pushing it down where you want it as it grows.