There where some errors in the name form. Names that where changed, couldn't be changed again (I'm using Firefox) & In the last form of Pride & Prejudice, The change I made on the last name weren't reflected in the text.
All & all, super & clever idea!
We could implement it your way, but since – as far as I know – grammar rules* diverge (allowing both orthographies), we opted for the uniform application of the possessive /’s/, which was easier to implement, too. What do you think: should we vary between books, based on the idiom of the original text, or should it be a user preference?
In our generic product, though, users will be able to select and apply their preferences for orthotypography, i.e. such things like single or double quotes (Oxford vs Chicago, British vs American). But when it comes to spelling per se, we will leave it up to the user to go with the ‘correct’ form of English of their liking, and leave the input text untouched.