I haven't read Moll Flanders, but Roxana lacks a single male romantic interest for the woman. It's long and very episodic, a string of mostly dark encounters and brief liaisons. In other words ... no great love, therefore no big pdd. Roxana is a great character and could, I suppose, be a great role for a dramatic ballereina. But I wonder if it would meet the expectations of your typical story-ballet audience. You'd not only have to cut out a great deal; you'd probably have to make up a love interest and redo the plot as well.
I don't know if I'd call Roxana's liaisons with the Prince and all the previous husbands and lovers dark, except that none of them, of which there are many, are much beyond 2-dimensional. But the novel is wonderful primarily for the writing style. But it's mainly about her constant upbraiding of herself for giving in to temptation and gold and ambition and feeling guilty about it. She is a courtesan, but refers to herself as a whore, but the problem is she has little range of character. She has her sidekick Amy and then tries to reform herself somewhat by helping out her abandoned children from a distance, but there are all sorts of messes that occur with those, and it's all in the written plotting. She's not quite a sympathetic character just because she says she isn't either--she is very repetitious and it's really only Defoe who's interesting. I can't well envision any of those 18th century novels as story ballets, although something abstract and shorter could be made about Roxana, perhaps more than Moll Flanders, Tom Jones or Joseph Andrews. I just see some big pageant of too many plot twists, too much scenery and costumes otherwise. POB did 'Wuthering Heights', but that doesn't seen quite the same. A one-act ballet of Roxana sounds possible, but not all that promising to my mind. None of the characters have any real romantic texture to them, although many of them are comic. Just a one-act piece with only the Roxana Name Dance focussed on with no moralizing could be dazzling, though, now I think of it: Just ignore the inevitable tragic ending and redo it completely, with just the whore-heroine at her social peak. This would be a totally unpunished whore (at least within what is shown onstage) and that would be something refreshing, but even though it's probably been done without pointing it out too strongly before, the world is probably as yet still not interested in something like that. So a 'Roxana's Dance' still sounds more promising than the Fielding, and Moll is too comic. How had you envisioned these, Ray? With all the complicated plot lines spelled out? For some reason, it reminds of a combo of what I read about POB Caligula and the awful Mayerling--on the heavy as lead side somehow. Maybe something primarily decorative is possible for these rococo things and loosely adapted. Actually begins to sound like 'La Valse', though.
As much as my limited imagination allows, I did envision radical adaptations/reworkings of these eighteenth-century stories. And I guess I was imagining a ballet w/out a traditional romantic narrative--instead, episodic like, say, The Rake's Progress (another candidate for a good ballet?). This would all depend, of course, on a masterful choreographer and dramaturg working together!
And I thought of those particular Mann stories because, unlike Death In Venice, they have a comic edge to them, to pull us away from the "death is sad" cliche of the Mahlerballet. Felix Krull could offer some wonderful opportunities for the male lead to have to act out different characters (Krull is a con man)---not to mention that scene from childhood where he tries on all the different costumes.
I guess a problem with all these stories is that they are often about solitary figures, and we all know about ballets with too many solos....