Your plans sound like my yard, six years later just finished establishing beds. If I grow it it is idiot proof. But I am in ZN 3/4 so you will have to tweek my plant choices. If you are getting your plants from a "store" in pots you can plant them anytime. Heat is a factor in success, how much watering you want to do. Wait a few weeks until things cool off and you will have less watering to do. I have Jack-in-the pulpits, astilbe, hosta, hosta, hosta, wild ginger, Solomons seal, trilliums, Bleeding heart, fern leaf and regular; lady, ostrich, maiden hair, christmas, japanese painted ferns. I love ground covers for weed control,creeping jenny,snow on the mountain, ajuga, sedums. I have Lilly of the valley, prim rose, wild geranium, cranesbill geranium...my list goes on. The variey givem me always something blooming. Bulbs, daffodil etc. are up and blooming before the oaks leaf out so I have flowers, small that they are from April until frost. I planted light colored hosta toward the back to lighten the space and draw the eye. Save yourself transplanting and put the larger part was clearing the beds. You could go woodland and look for natives.That is where i got all my jacks and stuff, deeper in the woods and brought up front. Good luck, and have fun!

I've just bought a new book that is better than anything I've ever read on shade gardening. You might try "Making the Most of Shade: How to Plan, Plant, and Grow...." by Larry Hodgson. He often mentions the difference between "shade" in northern vs. southern climes, which would be important for you to understand in the South. Easy to read, comprehensive, and not very expensive.