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They like well drained, organic rich soil that is slightly acidic to moderately alkaline.

I would not prune it back by more than 1/3 in any one year. Cutting it back further than that could harm the plant. This article should help with pruning: https://www.gardeningknowhow.com/ornamental/shrubs/lilac/pruning-lilac-bushes-when-to-trim-lilac-bushes.htm

On average, most lilac varieties are medium growers, meaning they grow about one to two feet annually.

While I can't say with certainty that it will survive, you could try to root the cutting. This article should help you with that: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-to-root-cuttings-from-various-shrubs-bushes-and-trees.htm

Most lilac varieties are hardy in Zones 4-8, so in South Carolina you should not have any difficulty growing them. In fact, many people down South enjoy these old-fashioned shrubs. Simply choose a variety that best fits your area's conditions. For help with your particular hardiness zone, this article should help: https://www.gardeningknowhow.com/planting-zones/south-carolina-planting-zones.htm

Most transplanting takes place in spring or fall (preferably fall). If you can ensure that the majority of the roots and surrounding soil is lifted and replanted in similar growing conditions, you'll have a greater chance of success. To reduce shock, trimming may help. Here is an article that you may find helpful: https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm