Stretching the comparison is fun and I like yours. I think their opposite characters lend to the S&S allusion--as you say not the same as in Elinor and Marianne but I see it too in the facts that Lucy is always in control and Anne is never able to control herself and also in that Lucy is Anne’s corrector—advisor—coach. Thanks for bringing this up—I think JA used both pairs of sisters (the Steels and LM & CP) to reflect on Elinor and Marianne so I am not inclined to see coincidences in any similarities between the pairs—it is my prejudice I guess. :D.