Lady Russell's prejudice and her disconnect with Anne's feelings: These are two very good points IMO, and well argued, if I may say so. I have nothing to add to your post, which is not a bit too long for me.

I have never really warmed to Lady Russell, but during the last 'Persuasion' GR I did come to appreciate that her concerns in 1806 about the financial imprudence of the engagement were perfectly justified.
This time around I have had such a serious falling out with the woman that I can barely express myself coherently on the subject. However, LR does love Anne, so I am pleased that she sees the light and redeems herself in Ch.24. It would have been a pity if Anne's new-found happiness had meant losing her mother-figure, one of the very few people who has really cared about her for many years.