I think both Charlotte and Louisa go well with Tabitha.
Or perhaps something else longish and slightly fancy sounding:
Annabelle, Arabella, Abigail, Amelia, Alexandra, Bethany, Beatrice, Cecilia, Cassandra, Clarissa, Delilah, Elizabeth, Eloisa, Eleanor, Elianne, Felicity, Francesca, Florence, Georgina, Gabriella, Henrietta, Harriet, Hermione, Helena Isabella, Imogen, Juliette, Julianna, Josephine, Katherine, Lucinda, Lilianna, Matilda, Miranda, Melissa, Madeleine, Natasha, Natalie, Ophelia, Olivia, Philippa, Rebecca, Rhiannon, Rosanna, Sophia, Savannah, Samantha, Victoria, Vanessa, Xanthe.