Pieris japonica is very attractive. You might want to ask on the Azalea forum about any issues planting more azaleas there after treatment with fungicide.

Not much of Texas offers soil conditions suitable for gowing azaleas, rhodies, pieris or any other acid lover without considerable and consistent amending. I'd consider shrubs like Nandina (heavenly bamboo) or Japanese holly for this situation - both are very shade tolerant and adaptable to a range of soil conditions, but they don't offer much in the way of flowers. Hydrangeas are another, non-evergreen choice. You can always supplement color with flowering annuals or perennials, many of which will be happy and flower well in mostly shade. If the area receives only part shade, you could try Indian hawthorn or abelia.

Why do you think you have a soil fungus? And why would a lawn fungicide necessarily be an appropriate treatment for a soil fungus? Has this problem - if there is one - been diagnosed or are you just guessing and trying a home remedy? Fungicides tend to be some of the more toxic of pesticides and I wouldn't recommend tossing them unless or until I knew for sure they were needed and registered for the problem.

I also live in East Texas and azaleas usually do quite well in this part of the state. Azaleas DO like some sun though and need ferile soiland at times fetilizer. Could it be the soil wasn't rich enough?? My azaleas actually prefer more sun that my hydrangeas so you might try those in that area. Have you considered a nice hosta and fern area? You could add some astilbe and other shade things. Hughs plant farm outside of Tyler has a HUGE selection of plants and you should be able to get a good start there. Also, there is a place on Hwy 79 outside of Jacksonville (and I think another place in Nacadoches) called Angelina County River Authority and they have the BEST compost I've ever EVER used. It's $25.00 a truck bed full and they will load it with a tractor.
I hope this was of some help.
Good luck,
Sunny