'Cinderella' is itself a sport of 'Fred Sander', which is also a sport of 'Lady De Saumarez'. 'Cinderella' also has two registered sports of its own: 'Raspberry Ice' and 'Robert Strauss'.
https://jimscamellias.com/came...
As far as I can tell, though, these are all semi-double camellias, so it does seem likely that the pink double flowers may be rootstock.
I have very little doubt that the flowers in your original photos are 'Cinderella'. The coloration, patterning and fringed petals are distinctive and unusual. But I have no idea if the double pink flowers also on that bush are a sport or (as seems likely) rootstock.
The variability of camellias makes them challenging to ID, but they certainly aren't boring!
Virginia