Is the painting all we have to go by or are all the pictures the same variety?

Trehane, CAMELLIAS - THE GARDENER'S ENCYCLOPEDIA (2007, Timber Press, Portland) has a picture of 'Miss Charleston' on page 188 that looks similar to your bottom photo in particular.

"South Carolina, USA. 1962. More often seen in its variegated form, with white virus-induced marbling; a great favorite on the show bench.
Flowers. Up to 15cm in diameter, semi-double to peony form, rich red. Mid to late.
Leaves. 10 x 7cm, dark green, slightly serrate.
Habit. Upright, with well-spaced branches. Moderate vigour"

that if you showed up at one of their meetings with half a dozen flowers and attached leaf samples that you could go home afterward with some good leads, if not a positive identification.

Notice which variety is being shown on this page.

Here is a link that might be useful: Coastal Carolina Camellia Society

Try this link

Here is a link that might be useful: CamellaiWeb gallery