To me, Shirley/Caroline has real "this should have been endgame" vibes (do I even remember the names of their eventual husbands? No. Do I remember that said husbands were brothers or cousins or something, meaning that their marriages would in some way work to bring Shirley & Caroline closer? YES.), whereas Lucy/Ginevra is much more "You should NOT be endgame, you have no DESIRE to be endgame... but clearly there is something going on with you two trainwrecks."