For Oliver and Joshua, I would stick with another 'contemporary classic' name - very popular over the last couple of decades, well established, very well liked, not at all controversial, unusual or 'out there'. Names like:
Annabelle, Amelia, Bethany, Beatrice, Charlotte, Chloe, Daisy, Darcey, Eleanor, Emily, Freya, Florence, Georgia, Grace, Holly, Hannah, Isabel, Imogen, Jessica, Jasmine, Katie, Katherine, Lily, Lucy, Madeleine, Matilda, Ottilie, Phoebe, Penelope, Rosie, Ruby, Sophie, Scarlett, Thea, Victoria, Violet, Zoe, Zara