As a little coda to this novel it's worth pointing out that in that otherwise unfortunate final wind-up chapter Austen still does something quite interesting. She actually gives the reader an alternate ending! I suspect that by the end of the book she had herself become aware that Henry Crawford had been so created as to reveal a possibly redeemable character.
Here is her outline of the way the novel ends in an alternate universe:
"Henry Crawford, ruined by early independence and bad domestic example, indulged in the freaks of a cold-blooded vanity a little too long. Once it had, by an opening undesigned and unmerited, led him into the way of happiness. Could he have been satisfied with the conquest of one amiable woman’s affections, could he have found sufficient exultation in overcoming the reluctance, in working himself into the esteem and tenderness of Fanny Price, there would have been every probability of success and felicity for him. His affection had already done something. Her influence over him had already given him some influence over her. Would he have deserved more, there can be no doubt that more would have been obtained, especially when that marriage had taken place, which would have given him the assistance of her conscience in subduing her first inclination, and brought them very often together. Would he have persevered, and uprightly, Fanny must have been his reward, and a reward very voluntarily bestowed, within a reasonable period from Edmund’s marrying Mary.
Had he done as he intended, and as he knew he ought, by going down to Everingham after his return from Portsmouth, he might have been deciding his own happy destiny."
All those implied 'what ifs" tease the reader and make us wonder if both Fanny and Edmund would have been happier with partners who complemented rather reflected them.
And thanks to all who contributed to the thread.