I love the name apply as as standalone but you could use it as a nickname for: Mary (the original), Margaret, Penelope, Paloma or Pomeline or Apolline.
I really like Mary with Louisa and you’re other faves (minus Maeve).
If I had to use your nicknames, I would use:
Louisa
Mary nn Polly or just Polly
Eleanora - so you could use Leni/Lennie, Nora or both (I like Lenora too but not sure about it with Louisa, so would be an either/or for me)
Or
Penelope nn Polly and Lennie
Madeleine nn Mattie
Susannah (or Aurelia) nn Sunny
Aurora nn Rory (but Aurora or Aurelia not both) but I also like the idea of Rosemary nn Rory (if not using Mary) as suits the rest of the names better. Caroline works too, I just don’t personally love the name.
If you use Polly esp as a standalone, I personally might think twice about Solomon - just to avoid a Polly/Pol and Solly/SIL. Maybe Philippa nn Pippa or Malachi nn Kai instead. I know we’re on girls, but Felix, Jasper and Otto/Otis could also suit.