Martha - sweet, I like it
Annabel/Annie - I like Annabel a lot but don't like Annie as a short
Catherine - like it but not keen on Cat/Cathy which might happen
Clemency - not keen. Prefer Clementine
Daisy - not keen. It's quite sweet. Maybe a bit overused
Natasha/Sasha - love Natasha. Sasha is quite nice too but I wouldn't abbreviate.
Jonathan - like it. Good, solid name.
Alexander - love it. Also love the abbreviation Xander
Noah - love it.
From your list I would choose Natasha and Noah I think.
Other ideas:
Miriam, Mabel, Marnie, Madeleine, Miranda, Molly, Arabella, Anika, Anoushka, Abigail, Amy, Anna, Alannah, Arianne, Caitlyn, Clarissa, Cordelia, Cassandra, Christina, Christabel, Caroline, Cleo, Chloe, Darcey, Dana, Natalie, Natalya, Naomi, Nia, Nyah
Jonah, Joel, Jacob, Joshua, Jeremiah, Anthony, Adrian, Alistair, Adam, Nathaniel, Nico, Nicholas
Children I know with names on your shortlist have siblings called:
Holly, Tessa, Zach, Henry, Louis, Rachel, Zoe, Alex, Meg, Harry, Kitty, Hugh, Jack, Charlotte, Antigone, Jemima, Florence, Rebecca, Isabella, Matilda, Abigail, Patrick, Felicity, Madeleine, Hugo, Imogen, Katie, Charles, Adam, Fenella, Alisdair, Harriet, Claire, Angus.