Q.Ligustrum Survival
Here in SC the 100 years’ flood put our ligustrum hedge underwater for approximately 2 weeks. They now stand with curled, brown leaves. Is there any chance they will come back in the spring?

Unfortunately you will need to wait and see.
The duration of the flooding causes the roots to suffocate.
Here are some links with more information.
https://www.gardeningknowhow.com/plant-problems/environmental/flood-damage-garden.htm
https://www.gardeningknowhow.com/ornamental/shrubs/ligustrum/growing-ligustrum-shrubs.htm