It's more about you using the quotes to show a character's development or show how a theme is conveyed through a quote. ie 'I defy you stars’ – ironic – Romeo is talking about going against fate and loving Juliet but the whole point of the play is that their love is fated. Like that point could be brought up if they asked how fate is presented within Romeo and Juliet. You don't have to have quotes from all the characters but one of my favourite quotes to talk about for conflict was "No, sir, I do not bite my thumb at you, sir, but I bite my thumb, sir" from the scene with Sampson and Gregory at the beginning. To be safe I'd say have quotes from: Juliet, Romeo, Lady Capulet, Lord Capulet, The Nurse, Mercutio and the Friar. If you want to go a bit more in depth you can talk about Paris, Benvolio, Tybalt, Lady Montague and Lord Montague.