You say the area under your pine is "all shaded and very dry".
Any of the above-mentioned plants will absolutely need to be watered at least for this summer, until they can get established. Once it gets a good root system you can taper off watering but keep an eye on it. The term "drought tolerant" doesn't mean a plant will survive with no supplemental water at all. Well, unless it stores water like a cactus.
Even in the shade, new plants need water every day, especially in hot weather. As it cools off and they grow some more roots, you can taper back to every second day etc. The pine tree itself will suck up a lot of water as well, another thing that will make it tough for any new plant to establish under there.