Eleanor is my choice for a name for a hypothetical daughter, out of these three, though I think I'd more likely use Eleanor as a middle name in real life. I like Elle as a nickname (and in fact went through a phase where I just liked Elle as a first name).
Marguerite is also a fun middle name - though I'd more likely use Margot as either a first or middle, to be honest (less fussy).
Isabella is the only one I don't like - too fussy / frilly / princess-y, despite its ubiquity. I much prefer Isabel, or even Izabel.
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